Walking around in the armour was much more fun when it was fully-powered. He'd spent hundreds of hours getting the user interface perfected – since the entire thing was basically one big user interface – so that it not only detected his movements perfectly, but also anticipated them based on the electrical signals in his muscles: there was no delay from when he swung his arm to when the armour did. It had taken him even more hours of practice to become fully comfortable with all the add-ons he'd built in starting with the Mark II – but it had been a lot of fun practice. Wearing the suit was almost like getting add-ons directly wired into his brain. Although, when under-caffeinated and de-suited, he did now occasionally find himself trying to open systems that he actually wasn't wearing, muscles flexing in patterns that meant nothing without the suit's ability to understand them.

Eventually, he'd get it to the point where it could just read his brain, but he quite wasn't there. Yet.

His body still ached – nothing to be done about that except wait for it to pass, given the absence of painkillers (probably for the best, in this company) – but in the suit, that didn't matter. Even if he was hurting – the suit let him compensate. The suit let him be more.

The guard standing watch outside his room was still taller than him, even in the suit – but to be fair, the guy had a completely ridiculous helmet (or rather, a helmet that would have been completely ridiculous anywhere other than Asgard; here it just blended into the general decor) that added at least a quarter of a metre to his height. It was marginally better than Loki's Christmas Apparel, at least, as it did not have any horns.

"I'll show them the way. You're dismissed," said a smooth voice from behind them, before they could ask for directions, and Tony absolutely did not jump. He turned to see Loki – yes, in full ceremonial armour, horns and all – walk up and clasp his hands together, smiling winningly. The guard bowed and left.

"Loki," Steve said, his voice admirably controlled. Tony just hummed, more interested in the confirmation of Steve's experience – Loki definitely wasn't a teenager anymore. In his ceremonial garb, he was an exact doppelganger of the Loki that had attacked Manhattan.

"Please, walk with me," Loki invited. Steve stepped up immediately, putting himself between Loki and Tony – who felt obliged to roll his eyes as he put the helmet back on. He'd thought carrying it would be better, but if he was walking alongside Loki, no fucking way. In full armour – even damaged as it was – he had a way better chance of surviving any trick that Loki might pull than Steve did, but he could see that Steve was going to be stubborn about it and there was no point in fighting about it while the Trickster looked on and laughed.

Asgardians in their path hurried to get out of their way – or rather, out of the way of one of Asgard's princes – but they never looked at the three of them. Hmm. So Loki wasn't exactly popular – that fit with all of the legends.

"I was interested in inquiring into your troubles," Loki said after a pause. His tone was mild, velvety almost – not harmless, but definitely benign. Tony wondered how much of it was an act – did Loki ever lie to himself? Thor had thought that he did, in his madness – but what about this version? Was this version completely crazy, too, or only partly insane? "Heimdallr's vision is superb, but even he has his – blind spots, and the arrogance to deny them." He smiled again, this time ruefully. "Arrogance is a common fault among we Aesir, unfortunately."

"Yeah-huh," Tony said. "So, what, you think you're gonna help either of us?" He raised an eyebrow, even though Loki wouldn't be able to see it through the faceplate – conveying body language while in the armour had a lot to do with the general feel. "Heimdall told us about the whole 'aliens from the fifth dimension' thing. You're gonna offer to help us with your right hand while your left hand plots how to stab us in the back?"

"From the fifth dimension?" Loki looked baffled. "How could one be from a dimension?"

Tony and Steve exchanged glances. "It's an Earth saying," Steve interpreted.

"Really," Loki said, bemused. "How strange. Regardless, your metaphor is unequal to the task of explaining the true situation. Think, rather than of a human body, of an Aspen forest – a colony of trees all sprung from the same root system, all technically part of one living organism, but still, they grow, and may be chopped down, individually."

"And we're – what, pine trees?" Tony threw out the first type of forest-y tree that came to mind. He didn't really spend a lot of time around trees. Well, there were palm trees, but those didn't grow in forests, did they?

"Just so." Loki looked pleased that he'd made the jump.

"Great. One problem, though – Heimdall was pretty clear about this being the super-special centre of the universe. So what does this make you – this you?" He poked a finger in Loki's direction, only to have Steve bat it down. Tony rolled his eyes again, but went on. "The root system?"

Loki shook his head. "A better explanation would be that the versions of us that dwell here are the first trees – the ones from which spawn all others."

It sounded credible. Plausible.

It completely contradicted what Heimdallr had said about this Loki being the 'brain' of all the others – about him being all, and none. Tony really didn't have any idea what the hell that was supposed to mean, but it did not mean that Loki was just another tree.

"Right. Sure. Okay, so this version of you just happens to be nice, and wants to help us from the goodness of its – your – heart," Tony said.

"Tony," Steve remonstrated him mildly, but when Tony took his eyes off of Loki's expression long enough to check Steve's, he saw that Steve was wearing a flat, stubborn look. Yeah, Steve was on Tony's side, no doubt about it – he'd caught Heimdallr's speech, too, after all.

"It was my daughter that alerted me to your presence within these realms," Loki said, and Tony's eyes narrowed at the abrupt right turn in conversational topics. Loki's voice softened, and he looked away. "We exchange messages infrequently. It has been a long time since she has been able to step foot outside her realm, or I within it – a long time since I have seen her face, seen how she has grown." He looked back, meeting first Steve's gaze, and then Tony's. "Tell me of her, and I will consider your news fair payment for my aid in returning you home."

It sounded – well, shit, Loki made it sound legit. He'd sounded just as legit as when he'd firmly denied knowing anything about Steve to Þrymr's face. The question wasn't whether Loki could like about something like this – because the guy's epithet wasn't Lie-Smith for nothing – it was about whether he would, in this very specific instance. So – assume that he was lying about his motivations. He'd asked about aiding them. What did he get from helping them get home?

The sounds of merry feast-goers were growing steadily louder as they continued to walk, echoing off of all the grand, arcing metal walls and ceilings. Tony mulled it over. A way to make them disappear – maybe permanently? If he'd wanted that, surely he could accomplish the same thing in a less round-about manner. Although, this was Loki – bag full of cats. Straightforward wasn't his style.

"I never met your daughter," Steve said. "Sorry."

Loki frowned. "I had thought otherwise, from her description... how did you come to be in her realm?" There was the faintest note of confusion in his question. Tony didn't trust it.

They turned a corner and emerged onto the edge of an open-aired feast-hall – or perhaps the term 'courtyard' would have been more appropriate, really. A dozen enormous tables, stacked high with platters, were surrounded by Asgardian men and women, in finery ranging from elaborate full plate armour (which looked like it shouldn't have withstood one good blow, but it was of Asgardian make, so it could probably take a smack from Thor's hammer and only be a bit dented) to a floor-length gown that was apparently made up of diamonds, and not a lot else. Tony squinted; the effect was a lot like wearing a dress made of glittery fishnet. The lady had the assets to pull it off well, though. There were guards standing about the edges of the hall, but there seemed to be no servants helping with the meal, although obviously someone had to have set it up; rather, when somebody wanted something, they called out raucously and were obliged by their tablemates lifting up a platter of whatever-it-was and passing it down. Some people had abandoned the tables altogether, and remained standing as they ate, clustered among the large – albeit not for Asgard – golden statues that were interspersed between the tables like signposts.

The table that they stood closest to was smaller than the rest, and raised up on a dais, although it was no less overflowing than any of the others. Odin and Frigga – at least, Tony assumed that the woman was Frigga – sat behind the table upon ornate thrones, their heads bowed together as they spoke in such low voices that, over all of the hubbub, even the armour's sensors had no chance at picking out what they were saying. Thor knelt near his mother's chair, listening intently, before breaking out into a smile and standing to jog off of the dais and over to one of the other tables. Like Steve had said, he was definitely older – his beard was, well, an actual beard, in the same style that the Thor from Tony's universe had sported.

"I've been slipping through universes for a while," Steve said. The look in his eye made it clear he didn't trust Loki – Tony approved – but he wasn't sure that Steve's tactic of going along with the villain for now was the best idea. What did Loki stand to gain? "It was just the latest stop."

"An unfortunate state of affairs," Loki murmured, too low to be heard above the din without the armour's sensors – or superhuman hearing. He paused at the steps leading down into the courtyard. "May I beg of news from you, then, Mr. Stark, or do you likewise have none for me?"

Time to make a decision. The lack of pursuit about Steve's situation... maybe wondering what Loki got from helping them get home was the wrong idea – maybe he should be wondering what Lokireally wanted to know about Hel. "Yeah, I met her," Tony shrugged.

"How did she look?" There was genuine concern in his eyes – a parent's worry for a child. Tony had never seen a look like that from his father – occasionally he'd gotten it from his mother, or from Jarvis, their old butler. After both Jarvis and his parents were gone, he'd seen it from Obidiah – a lot. He'd never know if even then it had been a lie, or if Obie had only become twisted later.

Tony smiled crookedly and let his body language convey the same sentiment. "I think she was bored." It was as good a guess as any – he had no idea what Hel had been thinking throughout their conversation. If Loki had something to gain from details – well, Tony didn't have any to give him.

Loki breathed out, disappointed and – relieved? If this was an act, he was the finest actor Tony had ever seen. Or was he just going to the old standby of mixing in truths with his lies?

"Helheim is not a cheering place," Loki said. "That she longs for other pursuits is not unknown to me, but as her father, I fear the toll that her realm's perpetual gloom may take upon her spirit. That she merely longs for – "

He broke off as Thor's voice rang out, loud enough to briefly quiet the hubbub, "Brother! And Steven and Anthony! You have arrived, at long last – I had feared the feast would go on for half the night without you!" Thor bounced – seriously, overgrown puppy – his way toward them, trailed by an entourage of other battle-garbed Asgardians carrying tall mugs of some frothy, golden, no-doubt-extremely-alcoholic beverage. "Come, sit with us!"

He urged them over to a table, but Loki smiled and declined, "I must pay my respects to our mother and father," before veering off toward the dais.

Tony watched him go with narrowed eyes, but all his attention was soon taken up by Thor, who slung an arm around his shoulders and urged him, "My friend, doff your helmet – we are all friends here, and with it obscuring your face you cannot partake of the mead!" He led them over to chairs, good-humouredly shoving away one enormous man – Volstagg, the New Mexico reports had called him – from the seat at Thor's left, clapping the back of it and urging Tony to, "Sit, and be merry! This is a time of celebration!"

Tony shrugged and flipped the faceplate up. Before another spot could be found for him, Steve claimed the next chair over – which was good thinking. They shouldn't get split up. Thor called for platters to be passed, and a moment later they had plates in front of them filled high with food, making Tony's mouth water so badly that he reached for the nearest flagon and took a long draught without thinking. It tasted like nothing he'd ever drunk before – like liquid gold, cherry-red from the forge, the metallic tang tempered by a honeyed sweetness. His eyes widened and he took another gulp.

"Tony," Steve said to him in a low voice. He sounded urgently concerned. "That's – are you sure you should be drinking that?"

Tony raised an eyebrow at him. "Loosen up, Cap – it's a party!" Okay, so maybe he should take it a bit slower – he could feel the alcohol hitting his system already. What percentage was this stuff – or was it ethanol at all? Screw it, he was starving, he'd gamble on his hosts knowing how not to poison the lowly mortals. He took a third swig of the mead – or whatever it was – and put the flagon down so he could tuck into the slab of meat – it looked like some kind of pork – that somebody had put on his plate.

It tasted, all puns intended, divine.

"This is definitely alcoholic," Steve said, picking up the flagon that Tony had been drinking from and inspecting it.

"No shit," Tony rolled his eyes, grabbing it back and washing down a mouthful of pork. "Might even be able to get you drunk, Mr. Super Soldier." He resolved to treat the stuff like shots – which... probably meant he'd had too much too quickly already, but he'd do his best to limit his intake from here on in.

Steve looked confused, but a bit relieved – what the hell was that about? "I can get drunk," he said, picking up his utensils and finally digging into his own plate. He paused after one bite, and Tony smirked at the look on his face – knowing that he'd been wearing the same look not a moment before. Food of the gods was heady stuff, especially when you were really freaking hungry.

To his right, Thor began a loud and versified recounting of their trip to Jǫtunheimr, drawing roars of laughter from the crowd. The sky grew darker as he went on, until small globes of golden fire bloomed overhead, like floating lanterns. Tony squinted at them; they were a bit fuzzy. How much mead had he had to drink? He checked his flagon discreetly, but somebody had filled it up to the brim again. Damn. He shook his head and pushed it away, but found that the meat now – while still savoury – had a peculiar dryness to it that made him long for something to quench his thirst. Damn it, he was not thirty-something anymore – he could have some self-control. He squinted and looked about the table for water, but had no luck finding any.

There was a burst of cheering and Tony turned to see Loki, now in female form, saunter down from the dais and over to their table, his hips swaying as he walked. When he reached the chair on Thor's right, he performed a deep curtsey that displayed his cleavage for the entire courtyard to see, drawing yet another burst of cheering – and laughter. Tony rolled his eyes. On his other side, Steve was busy being engaged by Green Arrow – aka Fandral, again from the New Mexico reports – who was going on about something called 'flyting'. Well, at least Steve was having fun, even if he mostly looked bemused by their topic of conversation.

The attention of the crowds turned elsewhere; a large, dark-skinned fellow with a truly impressive hair-style – no helmet needed when your hair could do that – had clambered up onto a chair to regale those nearby with a loud tale. His gestures were large and encompassing, made no less so by the fact that he seemed to be missing his right hand. Tony squinted – hadn't there been a myth about that guy? The pleasant, golden hum of mead in his blood made it difficult to recall.

"Týr has ever been the first to laud his own courage," said an amused, feminine voice in his ear. Tony turned his head to see Loki leaning down over his chair, his boobs – wow, that was a weird thought – pushed forward by the way he had arranged his arms. Tony blinked once, hard, and forced himself to look up at Loki's face, because damn, even if that was a nice rack, it was not the time to be distracted by a shapechanger's feminine wiles.

"The night deepens, and I'm sure there will be speeches, yet, enough to bore us both to tears. Please, it is but a small favour I ask: to know what my daughter said. It has been so long since we last spoke."

What was his game? Shit. Tony tried to kick Steve in the shin and get his attention, but ended up kicking a chair-leg instead – at least he thought it was a chair-leg. He put out a hand to shake him, instead, but Loki caught it in two of his own – and oh, he really, really pulled off being a woman well. His fingers were long and delicate, gently curving, feminine.

"She is my daughter, Stark," Loki said, holding Tony's eyes with his own. "Surely there is someone within your own realm whom you love – whom you would beg of news for, even from an unreliable source."

Tony swallowed, his mouth feeling uncomfortably dry. He longed for another sip of mead to wet his throat – and push away the dark worry knotted up in the back of his brain. Pepper Pepper Pepper – he licked his lips and conjured up a half-truth to offer the trickster – he didn't want to part with a whole, but he needed something to say, something to get Loki to show a bit more of his hand. "Yeah, well, she said she didn't like me, and I should get the hell out of her realm."

Loki frowned; like everything else about him in this form, it was graceful, alluring. "I doubt that. Were my daughter so opposed to visitors, she would break the Gjallerbrú instead of merely appointing Móðguðr to guard it. But you do not entirely lie... she did offer you an exit." His fingers twined with Tony's; with his other hand, he cupped Tony's cheek. His eyes locked with Tony's – and oh, that was what a god's eyes looked like up close – or a pan-dimensional alien's; near enough. Tony could have drowned in them; he couldn't blink –

"She offered oblivion," Tony snapped without thinking, wrenching his head away. The room spun at the sudden motion, lights trailing streaks behind them. He felt dizzy, stupid, intoxicated on mead and the bright green of Loki's eyes. Fuck, he shouldn't have drunk so much – wasn't that a staple of fantasy? Do not look at the wizard's eyes. Fuck Steve, too, and his fucking ideas about magic,why hadn't he interfered just now? What other magic had Loki worked?

"Did she now," Loki breathed – it wasn't a question, it was confirmation. Triumph. Shit. What did that mean? Had he seen something in Tony's brain? The other Loki had taken a pick-ax to Selvig's, Barton's brain, fucked them up and brainwashed them – could this one pull things out as well as stick them in?

"Loki!" boomed Thor from Tony's other side. His voice was deep, if not as deep as Heimdallr's, and it made Tony's head ache slightly. "Father looks to be starting the toasts – come, sit!" Thor bounded out of his own chair and drew out Loki's seat with over-exaggerated courtesy; Loki disengaged from Tony and glided across to the chair in one smooth movement, and the pretended to swoon into it among cheering and laughter.

As soon as Thor had retaken his seat, there was the sound of stone scraping against stone, and Odin stood. A moment later his staff came down upon the floor, with another one of those boomsthat made Tony's bones ache; aided by the mead, it also made his head swim. Silence reigned over the courtyard in its wake.

"My friends," Odin said. "My subjects. My sons." He turned toward their table with a slight smile, which Thor and Loki both returned with grins – Thor's open and honest, and Loki's like the Cheshire Cat's. "Today has been a most auspicious day, started in ruin with the loss of one of our most potent weapons – and ended in triumph, with its return!"

Brief cheering broke out, but was quickly hushed as Odin went on. "My sons today have proven themselves worthy of their titles as princes of this realm! And my eldest, Thor – rise."

Thor rose, slowly, one hand on Mjolnir at his hip – not in threat, but to draw eyes to it; he was still grinning happily.

"Thor – my son – this day, you have proven yourself worthy of a mighty weapon. You have earned its favour and its trust. Be known to all now as crown prince of Asgard, and moreover, as the God of Thunder, wielder of Mjolnir's lighting!"

The courtyard broke out into deafening cheers as Thor raised Mjolnir high over his head, shaking it in his fist. Lighting flashed and a crack of thunder boomed, just making everyone cheer harder. Out of the corner of his eye, Tony watched Loki – who was smiling, open and honestly, applauding just as hard – no, harder – than anyone else.

Tony leaned over to Steve and spoke directly into his ear. "I can't figure out what Loki's game is. I think he got something from me but – I don't know."

Steve leaned in as well, and Tony turned his head so he could reply. "We need to stick by Thor – we know we can trust him, at least. Once this whole feast is over we can ask him about getting home. I don't think anyone else here cares."

"You're sure we can trust him? He's cavorting around with Loki."

Steve shook his head. "Loki's always been his blind spot – but Thor's good people."

Tony frowned slightly, but let his expression clear as he sat back – only to gaze about in shock. He hid it quickly.

The courtyard was the same – overdone golden statues and all – but the people were different. Someone other than Fandral was now sitting on Steve's left – a woman wearing a sword and armour, her eyes like flint for all that she was smiling. One long scar ran down the side of her face. Tony would have pegged her as Sif – but the scar, that was definitely new. He turned to look at Thor, but he, too, had changed – most noticeably, he now had a full beard, woven into thick braids that reached down to the middle of his chest. The hair on top of his head had grown longer, too, and now pulled back in a loose ponytail – but he was still grinning, holding Mjolnir aloft as he spoke to the person on his right – who was not Loki, anymore, unless Loki had shapeshifted again, into the grim and dour-faced man that reports had identified as Hogun the Grim.

"Shit," he muttered, looking around. There seemed to be more people, too. He caught Steve's eye, but Steve looked just as shaken as Tony felt.

"We looked away and time slipped past," Steve said in a low voice.

"Right. We need to... keep an eye on that," Tony said, reaching for his flagon and taking a healthy swallow. Screw it, he was already drunk anyway.

The sudden sound of a rooster crowing echoed throughout the hall, high and loud enough to carry even over the multitude of conversations. All heads swung in the direction of the great golden rooster statue that was – apparently – not actually a statue. Tony blinked at it as it crowed again, sounding even louder in the quiet that had resulted.

"That's the third time that's happened," he said, not even bothering with the cock jokes this time because really, third time, it was done, and more than that, the number three seemed... important: a thought that solidified as the rooster crowed once more (another third time) before shutting its beak and resuming its statue-like stillness.

"You must be mistaken; Gullinkambi has not crowed since this hall was founded," Thor said, clapping him on the shoulder. The suit barely rescued him from going face-first into his plate. "It is an omen, then, of this feast's importance!" There was a slight but noticeable slur in his speech – huh, so Tony wasn't the only one getting sloshed.

"A good omen, or a bad omen?" Steve asked, as Tony shoved his plate away so he could put his elbows on the table and steeple his fingers in an impressive thinking pose. Maybe it would prevent Thor from trying to cause him to face-plant again. There was something – damnit, the mead made it hard to think – he shook his head violently, then vaguely regretted it when the action only made him feel dizzier. The cocks. Cock, cock, cock, he kept getting distracted by that word, but that wasn't the important word, the important word was the title, even he knew that and he'd nearly flunked his required English course at MIT, coasting by on a D. And the title of that myth, the myth about the cocks, that title had been –

"Oh, shit," Tony blurted, shoving his chair back and stumbling to his feet. He looked around wildly. Who among this set of drunken revellers would know – Odin. But Odin was nowhere to be found, although Tony would have sworn he'd been at the high table just a moment before... right before everything had changed. Shit.

"Tony?" Steve said, pushing back his own chair and standing as well. Quite helpfully, he also clapped a hand on Tony's shoulder, keeping him from swaying. "Are you okay?"

"The feast-meats do sometimes disagree," Thor said from his other side, sounding concerned. "If you are in need, there are places where you can relieve yourself – "

"No, no, nonono," Tony said, waving his hands. "The rooster, the crowing cock, shit, I am such a child, I am a fourteen year old teenage moron who lets himself get distracted with – three roosters crow, it's an omen, part of a prophecy – one from the myths that I read, because they've all matched up – uh, more or less, I don't think Steve and I were supposed to be there for the whole cross-dressing thing – "

"Your aid with the matter was greatly appreciated," Thor noted, because apparently he'd learned by now, whatever age that was, that sometimes the only way to get a word in edgewise when Tony had stuff to say (which was, he could be honest, all the time) was to just talk over top of him. A small section of Tony's brain that was not busy freaking out appreciated that; seriously, he could talk and listen at the same time just fine, all this 'waiting for other people to not be speaking' nonsense just wasted time, and did they have no idea how valuable his time was?

The rest of him continued right on with freaking out. " – right, but it happened, that's my point, Loki even told the same lies, I swear that Thrym quoted straight from it, and Brynhild – Modgud –Hel – they all match up, when you – my you, my world's version of you, none of it matched up, but here it does – "

He was vaguely aware that there was a growing bubble of quiet around him. It was not an unfamiliar bubble: it was the kind generated when somebody said something extremely awkward in the presence of someone respected. The familiarity was almost soothing - well, it wasn't as if the awkwardness bothered him, and anyway he was busy freaking out about the end of the world, social propriety could go take a hike.

"Anthony Edward Stark," said a cool, feminine voice, and his heart jolted. That was –

That was his mother's voice.

No, it isn't, a more logical part of his brain insisted. Maria didn't sound like that at all. And he knew it was true, it was, but there was something about whoever had just spoken – Tony turned, slowly, leaning on Steve for a bit more support than he actually needed. He wanted to go sit at her feet, rest his head in her lap, and let her stroke his hair while telling him how everything would be okay. How Father was gone to keep the bad men away, to make sure they would be safe. But he would come home soon, and until then they could have cocoa with marshmallows.

There was a clatter of scraping chairs as people got up to bow to the queen – or, in the case of Thor, nod respectfully, and then embrace her with gentle enthusiasm. "Mother," he said with a smile.

She smiled back at him, patting his shoulder, and said gently, "Your father has gone for a brief time, but when he returns, he would speak to you in council. Attend to him in his chambers, if you please."

Thor nodded. "Is it - ?" he cut himself off, but from the look on his face and the faces of everybody around them, they knew what he would be asking. Tony wondered if he meant Loki – or had something else happened that they hadn't seen, in this strange slippery timestream?

Frigga's face grew still, but her voice was steady as she said, "Go, Thor."

Obviously confused, Thor nodded again, and took his leave only slightly tipsily. Frigga smiled at the other guests, and even though she wasn't smiling at him, Tony wanted to bask in the warmth of it. Jesus. If he could find a way to bottle that effect – was it more of their 'magic'? The myths had said that sorcery was a woman's art, but –

"I thought that Odin was the magician," he said, eyes narrowed, as Frigga turned and left the courtyard, towing Steve and Tony along like ducklings in her wake. Well, Steve followed her, and sort of steered Tony along as well; it seemed his feet weren't up to carrying him anywhere that Steve wasn't around to keep him upright. Unlike Thor, his diction was still perfectly crisp and clear – so alien alcohol or no, he could at least keep that much of his dignity.

"It is true that my husband donned a woman's garb and learned our arts, but who did you believe had taught him?" Frigga said, leading them inside and up a grand flight of stairs. Her amusement was like strawberries on a warm summer's day. Wait, no, that wasn't right, Pepper was allergic to strawberries. Blueberries, then. He could see meadows and flowers blooming at her words, almost more real than the near-empty hallway around them.

"I think I'm missing something, ma'am," Steve said. Tony glanced at his face – his words might be polite, but his expression was like granite. Huh. The mother-thing was getting to him, too.

"Not so, good Captain," she replied. "You have wondered of the coming of Ragnarok, have you not?" She smiled again at his taken-aback confession. "Heimdallr hears all, and informed me that your suspicion might be pertinent."

She withdrew a key from a pouch on her belt – fanny packs usually looked ridiculous, honestly, Tony had never seen one that didn't look completely disco, but somehow Frigga managed to pull off the belt-pouch thing. Then again, she probably could have looked simultaneously imperious and motherly in anything from her birthday suit to a clown costume. The key unlocked an imposing set of doors (as if there were any other kind in Asgard) and she let them out onto the balcony.

Shouts and the sound of drums met their ears. Tony leaned heavily on the railing, no longer from drunkenness, but from the sight of it all. The sky had split in two, the stars above breaking in half and the void boiling out like eternal night. Below, tiny, far-off riders galloped toward Asgard along the rainbow bridge – but they left fire in their wake; chunks of the bridge were already falling, turning to ash and dropping into the sea below. The rider in front was so bright that it hurt to look at. Soldiers manned the walls of Asgard, but they were already besieged by another army, and even as they watched an enormous river of ice spewed forth from nowhere, sweeping over the left-hand walls and providing a road over the defences for the frost giants that now swarmed forth.

An enormous wolf, easily the size of a building – and in Asgard, that meant a lot more than it did on Earth – leapt the walls in a single bound and lifted its head to the sky. Its howl temporarily drowned the sounds of fighting, until it was met with the sound of a horn blowing – summoning war. Summoning the end times.

"This is our twilight," Frigga said calmly. Her dress blew back in the wind, unfurling out behind her like a banner.

"We can help," Steve said immediately, her words apparently hastening him to get over his own horror. "We'll help – where's your armoury, I need to grab a weapon. Iron Man, are you good to – "

"Captain, this is not your fight," Frigga said gently, placing one hand on his shoulder. As tall as any other Asgardian, she topped even Steve for height. "Nor is there anything you can do, for this is not the first twilight of the gods. As the day turns and renews, so do we."

"No offense, ma'am," Steve said tightly, "But I'm not the sort to sit and wait."

"Cap's right, we can help – save a few more civilians that would've been lost," Tony said tightly. "I've read those myths, we can save lives." He was about to pull the faceplate down, but Frigga's hand was suddenly resting on his cheek. His skin burned hot and then cold – when she pulled her hand away, all the alcohol was gone from his system. "Nice trick. Thanks," he muttered, and slammed the plate down.

"Captain, if you wish to fight, that is your right," Frigga said quietly. "We have many armouries on the main level of the palace, and they have been thrown open to all who would defend this realm or themselves. But I would beg a further moment of your time, Stark."

Steve and Tony shared glances. If they got separated now, in a realm under siege – well, hell, who knew what the odds were of coming out of this anyway? "Go, Cap," Tony told him. "Good luck."

"You, too," Steve clapped him on the shoulder, and then he was gone.

The HUD let him zoom in on anything. A dozen individual battles played out in his view, with the major scene compressed to the bottom half of the screen. "So what's still important even at the end of the world?" he asked Frigga casually. He'd spotted Odin, riding out on an eight-legged horse – oh, Jesus, that myth was true, too? – straight for the giant wolf. Was this where Odin died? He'd barely skimmed the latter half of the Ragnarok myth – it got kinda repetitive after a while. He dies, she dies, we all die.

"There are many myths of Asgard, spread across many worlds," Frigga said. "As our personalities spread, so do the tales. But the true prophecies have always been kept here – although even they may be proved false. Since your arrival, you have spoken of truths that no mortal should hold, and intimated that you know more. Heimdall has searched on every world and he can find none where the legends match so exactly. So, I must ask: what are you, Stark? Did my son bring you here, hoping that your presence would disrupt the course of history? Did he conjure you that you might take an active role in that disruption?"

The frost giants and the fire giants were fighting each other, seemingly without regard for the fact that they both stood on enemy soil. It was a brutal, chaotic melee, no holds barred. Tony hoped that Steve would have the sense to stay well away from that part of the fight – nobody there wanted or needed any help.

"Look, as far as I know, I fell here by complete accident. I just want to get back to my world," he said seriously.

"You saw things, as you fell," Frigga observed, " – is that where you learned these truths?"

The giant wolf snapped Odin up in his jaws and tossed him skyward; a second snap, even as Odin lashed out with his spear, and the All-Father was gone, swallowed whole. A warrior – who nearly resembled Thor, but without the cape and hammer – launched himself at the creature, mouth open in a scream and face fixed with rage. There was a flash of a sword, and a great gout of blood spurted from the side of the wolf's face as its jaw drooped open, unhinged.

"I saw stuff, there, yeah," Tony acknowledged, focusing on the fight. Blood and guts he could handle far better than the memory of that impossible curve. "But nobody was reading me fairytales."

"My husband hung there for nine days, to earn wisdom – but he did not fall," Frigga said quietly. "My son Loki fell for an eternity and returned far changed. You know the thing that lurks there. I can see the cracks that it has made in your mind."

Tony shuddered involuntarily, but the suit absorbed and hid the motion. "Yeah, and that doesn't make sense," he argued, because either way – well, either way sucked, as far as his options went. "Hel's Loki's daughter, she controls the – thing, why does he have a problem with it?" Below, the wolf, burdened by blood loss, was too slow to dodge, and Odin's avenger thrust a spear into its heart. It shuddered, then fell, the impact loud enough to be heard from their far perch.

"My grand-daughter is dead," Frigga said, and her voice could have been made of ice, salted tears from a dozen bereft mothers, frozen in the cold of deepest winter. "She was born dead, and was dead long 'ere my husband appointed her queen of the only realm in which she might find solace. Things that do not have the breath of life cannot have it twisted within them, or ripped from them, and thus they are both protected from and bereft of the truths that the living might see. My son, however," her voice dipped, low and mournful, "he has been changed by it – too much so, I fear. And your continued presence here, spouting myths that you should have no knowledge of, prophecies that are truer than our own, alarms me greatly. Look," she raised one hand elegantly to point down at the battlefield. Tony refocused one of his cameras and saw Loki and Heimdallr, fighting, spear against mighty sword. Both had taken wounds. Loki wasn't wearing the green-on-black armour he'd had before; what he wore now was closer to half-plate, if any armourer would make the plates from bones. It gleamed sickly white.

"Loki kills him," Tony muttered. "I remember that part, it was one of the parts right before he summoned the giant snake."

Frigga looked up sharply. "The foretelling holds that they slay each other."

The sky opened up. Fire burst from the heavens, like a million blooming flowers; Tony slid sideways and clanged against the railing as gravity seemed to lurch about. Frigga was unaffected, her hand never leaving the rail – and then gravity went back to normal, leaving him half leaning over the railing and hanging on for dear life, even though he could fly.

So far away, Loki brought his spear down, around, parried the sword, and buried the spearhead in Heimdall's stomach. The watcher didn't even flinch, bringing his sword up and around, darting in at Loki's neck – but one hand whipped up, a dagger held to parry; the sword skittered up and over Loki's head from the redirected force of the blow. Savagely, Loki ripped the spear back and slashed its end down across Heimdallr's throat, in under the protection afforded by his helmet – and the larger god collapsed, blood spurting from the arterial wound.

Tony felt sick. Paralyzed. He'd just watched a man – well, okay, a person – die and he hadn't been anywhere near the fight. These people weren't human, but he knew them, and even if they were shitty people they were still dying right in front of him while he did nothing –

"The myth has changed," Frigga whispered, looking at him, afraid. "What has your presence here done, Stark? How has our world become slaved to your myths, undoing the wills of the even the norns? Will this be our final end?"

"Wonder all you like, but I'm gone," he snapped, activating flight controls as he stepped to the side away from her. A moment later he was soaring away from the balcony, repulsors flaring as he locked onto his target.

"JARVIS, same as before, keep an eye out for illusions," he warned, because he'd seen the tapes of how the bastard had killed Phil. "And watch out for Cap, too." He passed over the ice-road as he flew, and blasted it with the repulsors on the far side, chipping out a gap – pity he didn't have any missiles left, but he'd used all of those up in Manhattan. He levelled out, close to the ground even as combatants leapt in his direction – and then he went supersonic.

The shockwave knocked the closest ones off their feet, but he didn't care about that. He slammed into Loki at Mach 3, hard enough to reduce any human to paste – hard enough to knock the wind out of a god. Loki was limp in his grip for only a second, and then he was clawing at the suit, his knives somehow managing to cut through the plating – goddamn alien technology. Tony initiated evasive manoeuvring and threw him off-balance again, and then tossed him off with a full-power repulsor blast as one of the knives got way too close to his neck.

Reality jolted. The skies weren't above or below him – they were right in front of him, replacing the sea, as overhead one of the enormous roots of Yggdrasil writhed in pain, burning. Somewhere out there was the Níðhöggr, and he curled himself up into a ball rather than risk seeing it. JARVIS had amped up the volume on the internal speakers, and was demanding, "Sir, diagnostics do not show damage, what is – " but he could barely hear it as he screamed, as loud as he could, to keep any sight or sound of that creature at bay.

A long moment where there were stars rather than water, and shadows where there had been light, and fire where darkness had reigned – and then it snapped back, sending him tumbling across the ground, hard. He scrambled to his feet, snapping at JARVIS and scanning for Loki. Where had he gone? Corpses surrounded him, and some not-quite corpses – he was still near where the wall had been breached. In the distance, the golden towers of Asgard were burning, and one had already collapsed, jagged and smoking. He couldn't be concerned with that, though, not when –

"Watch out!"

Steve, Tony thought. Instincts forged of shared battle had already kicked in and he'd fired the thrusters, thrown himself tens of metres into the air in a blink of an eye. Below him, blue fire exploded, leaving a crater where he'd been standing, and he whirled to see Loki vanish just before a wooden shield would have bashed through his head. It arced, but not far enough to return to Steve before Tony landed. Steve didn't go after it, though, just scooped up a nearer shield that had been discarded by some fallen warrior. It matched the sword he was already carrying.

"Loki's changing things from their myths," he filled Steve in, grabbing him and taking to the air again – they needed up, they needed a view of what was going on. "We need to find him and take him down before he ends everything. Where's Thor?" They might be able to take Loki on together, even without Steve's shield, and the armour already damaged and low on ammo. If Steve could pin him down long enough for Tony to get a clear shot with the lasers, that might work - but they couldn't afford too many tries; the lasers drained power like crazy. Thor could summon lightning – he could turn the course of this entire battle.

"On Earth," Steve shouted over the wind as they flew. "Odin sent him there before the bifrost fell. It's up to us."

"Great," Tony started to say, and everything turned upside down. The ground and the sea were above them, splitting open – enormous coils filled the void, scales sliding against scales as the body of an enormous snake writhed – the stars were below them, but they were the wrong stars; they were the stars of earth, and the stars of the Chitauri, and the stars of Asgard, all laid over top of each other and being crushed together. Their light was the brightness of a thousand dying suns. He wanted to hide but he couldn't drop Steve –

It snapped back again and he righted them automatically. Somehow, probably thanks to JARVIS, he hadn't dropped Steve. "That – that's happened before. What is it?" Steve asked.

Sensors located a flash of green and gold. Tony tightened his grip and sped up – having Steve there would be better than just hitting Loki again at supersonic speeds. "Yggdrasil's dying," he said grimly. "Didn't you see the root?"

Steve's response was muffled by the wind, but the sensors managed to clear it up enough to be intelligible. "No – are we seeing different things?"

"Maybe. Ready?" They were near – he barely had time to register Steve's nod before he was throwing him in Loki's direction. Steve hit shield-first – the wood shattered, and Steve flipped away as Loki snarled and swung his spear outward. They parried, lightning fast as Tony dove behind them and flattened a half-dozen frost giants, then brought his arm up as soon as he had a clear shot. The laser mount opened up.

Loki caught Steve's wrist with a blow from his offhand, sending Steve's sword flying; as Steve rolled away, regrouping, he flicked the spear around and intercepted the red beam with the glowing blue spearhead. The laser reflected back, flashing about at odd angles, and nearly cutting Tony's leg off before he killed power – it left a scorch down the side of the left thigh, melting the paint job, and he cursed. Then he had to dodge to the side as a bolt of blue fire came his way.

"Old fashioned way, then," he said grimly, raising his hands palms-outward, and that was when reality shivered again. The ground went loose beneath his feet, and he staggered – overhead, somewhere, was that thing, and underneath, and he couldn't move, could barely breathe, unnatural fear swamping him mind –

It corrected, again, and he tried to move, to take off – but he'd sunk into the broken ruin of the ground, and rock had solidified around him, leaving only his head and his left hand free. A few yards away Loki rose to his feet, saw Tony's predicament, and smiled.

Steve attacked him from behind, landing a kick to Loki's head that sent his stupid antlered helmet flying; Tony felt like cheering. "JARVIS, analysis," he said instead, already aiming a few experimental repulsor blasts; he got most of his neck free, but aiming was a problem with his wrist so encased – he needed to get his arm free. Steve couldn't take Loki in a straight, one-on-one fight, but Tony could hope like hell that he'd buy him enough time.

Loki caught Steve with a glancing blow and dropped the spear, bringing his suddenly free hand around and clamping it down on the side of Steve's neck. Green-blue light flickered about Loki's hand and Steve collapsed with an agonized cry. Tony tried to meet his eyes, but the angle was all wrong – Steve was trying to get to his feet, trying and failing, his limbs twitching like he'd been electrocuted. Calmly, Loki retrieved the spear, and raised it high.

Steve vanished.

Loki raised his eyebrows – so much calmer, so much more understanding than he had been when, barely two days before, he'd tapped his Sceptre against Tony's chest and it had failed to make him Loki's bitch. "Ah," he said, in that drawn-out accent of his. "Inconvenient timing – as always – but little matter. He will die in the end." Smiling his half-smile, he turned and strolled over to where Tony was still mostly trapped by the stone, little chips of it scattered around him. Tony cursed under his breath; just a little bit more and he could angle his wrist properly, god damn it –

Loki gently set the butt of the Spear down upon his hand, breaking it free of the stone and pinning it down as surely as if he'd nailed a spike through it. Then he knelt, patiently waiting until Tony stopped grunting and grimacing and trying to free his hand, and instead looked up back at him.

"Every single universe," Loki mused softly, "and you always bring this upon yourself." He waved a hand languidly at the stone. "You throw yourself in front of him, in front of all of them – so desperate to die. And you always fail to do so. Whereas he – " a scrap of Steve's flag waved from between Loki's fingers, " – he dies. He throws himself on the wire."

Tony stared back and tried not to swallow. Was it chance? Or had the god pulled that from his mind? He tried to pull his gaze away and found he couldn't.

"He always dies, Tony," Loki said, and the name sounded so goddamned intimate on his tongue. "He becomes ensnared up in your plans and takes a bullet to the heart. He commits suicide to save your nation and your world. But you," and Tony saw the vast roots of Yggdrasil in his eyes, "you, who have striven so hard to be a martyr, to lay down as the sacrificial lamb and be forgiven – in every world you are denied. And I see no reason to discontinue that trend, to spare you the sight of Creation come undone."

Stone crept over Tony's hand, trapping it, too. Loki stood, and the stone rose with him, keeping Tony on eye level with him and helpless. Well, almost helpless. "JARVIS, blow everything," he said quietly, on the internal comm only.

"Sir – "

"No." Loki laid one long finger upon the helmet's forehead. The suit went dead and silent as all power was sucked out of it, and Tony felt something click near his chest – the thin cabling to his personal arc reactor disconnecting. Without that connection, he couldn't use it as a backup. "This is my promise to you, Stark. You will survive Ragnarok. You will watch the worlds die and fall into everlasting night. And as you wander the ruins, eternal, you will know that you did this."

No. No – this wasn't his fault, for once, none of this had been his fault – had it? "The world reforms after Ragnarok, you ignorant twit," Tony snapped, quick and unable to be shaky with the suit holding him still.

Loki smiled. "Not this time."

The world went sideways. Stone cracked and groaned, but Tony couldn't take advantage of the opportunity to try to pull free; he was busy craning his head around, trying to figure out what was happening this time. Some part of him registered that, in front of him, Loki was doing the same, with the same look of fear on his face as Tony knew he himself wore. But this time it was water, and rain, and rocks – and something monstrously large in the dark –

"LOKI!"

Lightning thundered down and turned his vision white.

" – it has been an hon – "

"Cancel that!" he ordered quickly. "Cancel, sorry JARVIS, you got knocked out for a sec – put everything back into the repulsors, we're getting the hell out of here – "

"With the repulsors also encased, this method is unlikely to – "

"Unless you've got a better option I don't want to hear it," Tony cut him off, gritting his teeth. After only a few blasts, his hands were already becoming numb – a welcome relief; his abused left arm had been protesting in earnest – and the diagrams from the suits sensors showed that progress was going even slower than before. He was chipping the stone, all right – but the chips had nowhere to go, and they acted like a buffer between the repulsors and the unchipped stone, getting turned to fine sand instead of passing the force on.

He couldn't see Loki. "Where is he," he muttered, but having so much of the suit encased meant that the external sensors were reading a whole lot of rock and fuck-all else. The sky was darker than it had been, all the stars obscured by thick, rain-choked clouds, the type Thor liked to play with – which made sense, because that had definitely been Thor's voice – had the worlds crashed together, then? He could no longer see the towers of Asgard; was that because he was elsewhere, or because they had fallen?

Something slammed into the stone, and he went flying, spinning nauseatingly before hitting with a bone-jarring impact. "JARVIS – " he began, but JARVIS was already replying, "That appears to have caused exploitable fractures, sir," diagrams lighting up with the information. Tony took advantage accordingly.

But he couldn't help but watch – even though he was now lying tilted on his side, the world at a 108-degree angle from up. The sky crackled with lightning, which flashed down, again and again. By its light Tony could see what had hit him: a serpent, the serpent that had loomed in the sky, so large it made him snort with disbelief. It had thrown him uphill, and from this vantage point, he could see coils upon coils that bunched and flowed, each at least three metres in diameter, the scales glossy and black. There was no end to it – the coils went on and on, and although Tony could see the head – that was where Thor's lightning was striking – he couldn't believe its tail ever ended. The thing was just too massive.

In the heart of the storm he had created, Thor raised his hammer high, and let it fall.

The pulse of lightning reached even Tony, momentarily blinding him; it would have been more than momentary, if he hadn't had the faceplate down. "Repulsors," he snapped, before JARVIS asked him what to do with the additional power. The massive coils of the serpent shuddered in their death throes, but none slammed into him again – a pity, he thought, since he could have used the help. He could almost wiggle his arms – he was getting close to freedom –

The clouds lightened, beginning to disperse. Thor, standing in a small crater within the corpse, stood wearily. Gore clung to him, dying his blond hair and beard red – now, fresh from the battle and sporting wounds of his own, he at last fully matched the descriptions of the Norse myths. It all turns out true, Tony thought as Thor began to walk towards him, and then his brain went and parsed that again.

Thor was walking towards him.

Ragnarok – slay the serpent – walk nine paces –

His brain replayed. Thor was walking towards him – three steps –

"Stop!" Tony shouted desperately, but Thor didn't seem to hear him, taking another slow, unsteady step. "Thor, STOP! Stop walking, just – stop, stay there – JARVIS, increase the damn power – " He had to get out, he had to get out!

"Sir, the left gauntlet repulsor is sustaining damage," JARVIS warned.

Thor looked up at him in concern, pausing, and the relief made Tony feel light-headed. "Anthony – are you injured? I will free you," and Tony could hear his words begin to slur from the venom. He'd been bitten – where? –

He took another step, and Tony yelled, "No, no, damn it, don't come any nearer!" as he took another.

Thor held up his hand, and declared firmly, "If it is a trap, I will brave it nonetheless," even as his voice shook, and he'd taken two more steps, ignoring Tony's curses.

"You'll kill me!" Tony shouted, and finally, finally, that lie stopped Thor, on eight fucking steps, and he looked up at Tony with confusion written all over his face. The armour's main camera zoomed in when Tony unwittingly locked his eyes onto Thor's for too long; the god was ashen, his eyes unfocused.

"Just – stay," Tony pleaded with him. "I'm nearly out, and then that'll be good – " The rock gave overtop of his right repulsor, and if his hand had long since gone numb, it didn't matter. Tony whooped as he pulled it free of the stone.

Loki reappeared, halfway between Thor and Tony. He wasn't wearing his helmet. Instead, his hair was loose, unkempt, and instead of the bone-plate, his armour was the same as it had been when they'd all walked out of Jǫtunheimr together. "Brother?" he asked tentatively, raising a hand.

Thor's face was a picture of surprise, both wary and pleased. One hand went to Mjolnir, but the other went up, reaching out almost reflexively, because Thor was the most dependable, predictable moron who ever fucking lived, automatically taking a step towards his brother –

No, no, NO!

Thor blinked and fell to the earth, and was still.

Tony was already sending a full-power repulsor blast towards Loki, but he flickered and disappeared as reality twisted inside out. He might as well have been nothing more than an illusion, except for his voice – his voice was everywhere; it was all Tony could hear. Neither JARVIS nor the suit's automated warnings could break through. The mocking laughter made his spine crawl, and beneath it was a hissing whisper that bit at his ears: "My promise to you, Stark."

The sky snapped back, and it was black and filled with stars. Tony stared out at it, and out at the monstrous coils of the snake that were now nothing more than so many tonnes of dead flesh. Mechanically, he brought his right hand around and started chipping his other arm free. The left-hand repulsor didn't seem to be working anymore – when had that happened? His brain – his wonderful, horrible brain – informed him it had cracked upon the seventh step. The hand-done repairs he'd made to reattach the repulsor couldn't match the original machining.

It took him a while to free enough of his body that he could fire the boot repulsors and launch himself out of the rock. Reality groaned again before he was half-way done, and the darkness was replaced by flames that lingered even after it had returned to normal – if he could consider any of this 'normal'. Where the towers of Asgard had been, now pillars of fire soared up to the heavens, giving off thick smoke that obscured the stars.

Tony kicked skyward just in time for another wave of wrong. The time between them seemed to be increasing. Below him, the ground shuddered and crumbled, and waves from the shore crashed over dry land, washing over the dead serpent. Tony thought of all of that flesh, putrescent and rotting, floating about, and almost gagged. Thor's corpse was quickly covered as the water rushed inland; weighed down as it was by armour and hammer, the initial flood of water barely stirred it. Perhaps that was for the best. The last glimpse that Tony caught of Thor's face showed him decaying, purple-green flesh beginning to tear free of the skull – the venom was potent even after its victim's death.

Great gouts of steam billowed up from the ruins of Asgard. The flood had taken barely a minute to reach that far. Behind the broken towers, the mountains were much diminished, their snowcaps burned away, but they, at least, still stood – for now. They were as black as everything else, covered in soot. Some part of Tony marvelled at the speed of the destruction.

The suit's sensors couldn't pick up any survivors. There had to be – but everything that had been close to the shore was covered by the dead serpent's body. He flew inland, slowly enough that he could look for any trace of the living, but even after he passed the outer walls of Asgard and left behind the serpent's carcass, all he could find among the floating debris were corpses.

Atop the breach in one of the walls, not yet washed away, lay Heimdallr's body. He was no more dignified in death than Thor, his pose crumpled and his face gone slack. The bodies of frost giants lay littered around him – those that he'd killed before he'd so unsuccessfully dueled Loki. Some ways beyond him, the massive body of the wolf that had eaten Odin was swiftly being covered by the waves, its matted fur already soaked through. Its killer was perched atop its head, with half his face burned away; in turn his killer, a fire giant, lay dead on the beast's back, smouldering in the damp fur.

Reality flickered. Tony tried to order the HUB dead, but he had no voice. All the stars had gone out, leaving everything dark – but somehow, even without light, he could see the thing that stirred in the void, see the gashes it had made in the enormous, dying roots of Yggdrasil. The tree groaned and writhed, its death throes heaving about space itself before it finally split in twain, sending splinters the size of planets flying. Tony was tossed headlong, screaming as he caught a glimpse of the Níðhöggr's impossible spine.

He crashed into something as the universe gave one last shudder and the Níðhöggr vanished. Pain lanced up his neck as the armour bent under the force, but he didn't care – that thing eating into his brain was gone, at least for now, and he groaned in relief. "Sir," JARVIS said worriedly, saying something about his surroundings, but Tony didn't care. He just wanted to lie there for a while. It had been – it had been a shitty day all around, he wanted a break.

He wanted to go home, but he wasn't sure that existed anymore. He wanted to see Pepper, to hold her and tell her that he loved her – but if she was gone...

Tony forced himself to his feet and shook his head violently. If he let his thoughts run away from him then he'd end up laying down and dying. There were still stars here, there might still be other people alive, no matter what Loki had said – Loki Liesmith, Loki Silvertongue, why the hell would he believe what Loki had said? He launched himself into the air, leaving behind a small crater.

"JARVIS, prepare a full-spectrum sensor sweep – anyone still moving down there, I want to know about it," he ordered as he gained altitude. The ground dropped away beneath him, although the stars became no brighter. Over the edge of the world, where the sea still flowed into the abyss – so where did the water come from to replace it? – he caught a glimpse of a blackened sun, the last burning embers in its heart slowly fading away.

"Sir, there is something else I believe you should direct your attention toward," JARVIS reported, while Tony stared into the heart of the dying sun. In the lower corner of the screen, JARVIS popped up a zoomed-in version of something sitting on the edge of the sea, at the boundary of space: the dome of the bifrost machine. It didn't appear to be supported by anything – but then, the rainbow bridge couldn't have supported it in the first place; whatever supported it must have been invisible all along. It had clearly taken damage: there was a hole blown in the side of the machine, and the entire thing sat on a tilt, looking ready to fall into the void at any moment.

If there was any way off this planet, it would be that machine.

"Good catch, JARVIS," he said, and took off for the sea.

He'd made it barely half a mile before he spotted the Níðhöggr again. It appeared seemingly from nowhere, and he nearly fell out of the air before the autopilot kicked in and JARVIS had the presence of mind to turn cameras off. Skimming low over the water brought him some measure of protection, and he dropped behind the last patch of half-submerged ruins, trembling as he sought to put anything he could between it and him. Fractal teeth, their every point bending light, chewed on corpses as it flew, low to the ground. A bizarre paradox of a limb reached out and snatched another corpse – which moved weakly in protest, even though IR read it at the same temperature as its surrounds. A living corpse.

"Shit, shit, shit," Tony chanted, "JARVIS – fucking hell! Get us out of here!" The thrusters kicked in without further input and he shot away, going supersonic as he left the ruins behind. The Níðhöggr dipped behind far-off hills and disappeared from his mind's eye.

"Sir, I cannot perceive whatever it is that is causing you such distress," JARVIS reported.

"Does that mean you count as dead?" Tony asked shakily as he approached the edge of the world. The remains of the bifrost machine loomed, an aged relic of a great civilization now gone. A civilization that had been great right up until about an hour ago, Jesus.

"It more likely means you are incapable of programming me a soul."

Below him, the water atomized as it fell. Droplets broke into particles, particles broke apart into bits too small for the suit's sensors to pick up. On the macro scale it should have shown up as mist, but instead, beneath them there was only the black sun, sinking into endless darkness. The water entered the void and ceased to be.

"Scandalous lies, JARVIS, your programming is sublime – I should know, I wrote it myself. Heads up; let's not check out what's on the flip side. Or send this thing over the edge..." he approached the machine warily from the underside. An enormous crystal sat at the centre of it – was that its central heart? It was connected to four fin-like structures, which looked like they could be moved about. The fin nearest to the bridge side was smouldering, half of it missing. "Scan everything," Tony ordered, the magnitude of the task making his heart sink.

The chance to get his hands on alien tech and figure out how it worked should have been inspiring. It should have had him throwing a ticker-tape parade in celebration. Instead, alone in a dying world, where an impossible creature went around chowing down on corpses, it became daunting. He was on a time limit numbered in days if not hours, facing a problem that even he might need a lifetime to solve.

The initial results popped up and he cursed. The crystal was definitely important: Nanoscopic runic structures were engraved on it hundreds of layers deep – and likely further, but the suit's abilities only went so far. It was lucky that they could pick up that much at all – but he'd designed these particular sensors with the idea in the back of his head that it might be nice to be able to easily and surreptitiously scan in the full details of any hardware that he'd run across. Unfortunately, while human chips tended to be limited to a generally two-dimensional layout, the bifrost definitely wasn't. Even without counting the 3D layout, the space covered was enormous – the central crystal was metres across. "Great," Tony said. "JARVIS, spot-scan – look for patterns, give me samples, we're not gonna be able to store all of this."

The central crystal was just the beginning. He carefully peeled back the paneling on one of the intact fin structures and found more crystals, more 3D runes, more everything. He rolled the protective cover back into place and went after the others, finding to his dismay that they were all different – there were patterns, definitely, but at a glance he could see unique variations everywhere, and that didn't bode well for trying to repair the broken one. And he hadn't even gotten inside the thing yet. Not to mention what might be inside the walls... and if he ripped off the panelling on there, he might break the damn thing even further.

But he had the suit – the powered suit, which meant, really, that with time and enough raw materials, he could make an entire lab; start by reprogramming the repulsors, rely on the stabilizing agents, and he could do intricate work just as well as he could build himself a forge. Raw materials he might be able to find in the ruins... if he could do so before the world finished ending. Time... that was a problem. Even setting aside the need for food and fresh water, the Níðhöggr was still back on the mainland. Just the thought of flying back in that direction made his stomach twist with fear.

"Shit," he mumbled to himself, as he kept going through his scans. He'd watched Loki so carefully, but – well, Pepper sometimes watched him play with holograms – she sometimes played with them herself – but she had no clue how the interface was built. She didn't need to know – he did.

Going inside was a delicate operation. He didn't want to set foot on the structure – he didn't want to be the straw that sent it over the edge, not when he still hadn't figured out what was holding it up in the first place. Balancing carefully on the repulsors, he stripped the paneling on the central column, on the floors, taking scans. Whatever had blown a hole through the side had also burned gashes into the floor, fusing bits of crystal and metal into useless lumps.

He needed to go back and get Heimdall's sword. At the rate the water was rising – or rather, the rate the ground was sinking, since the bifrost appeared to be no closer to the water than it had been when he'd looked over the edge of the rainbow bridge scant hours earlier – Heimdall's corpse was probably already covered, and he'd just have to hope the weapon hadn't washed away. "Shit," he muttered again.

"Scans are as complete as data storage capacity will allow, sir, but without a basic understanding of this technology, a great many calculations will be required before I can even begin to hypothesize a starting point for repairs," JARVIS informed him.

"Uh-huh, you and me both," Tony muttered. He would probably be quicker at putting it together than JARVIS – although JARVIS was definitely smart, he thought differently, in a way that hindered his ability to make broad, intuitive jumps, at the payoff of being able to spend a truly obscene amount of attention on details. But it would still be a monumental task... and one that he might be able to lessen, if Asgardians had anything like libraries. Which, if they existed, would be back on the mainland.

He had to do it sooner or later. Tony took a deep breath, in and out, and then said, "Bring up Heimdall's last location on the HUD. Might as well pick up his sword on the way."

One library had survived. Barely. Whether it would be of any use or not... well, the jury was still out on that.

For such an advanced civilization, the Asgardians seemed to enjoy over-much an extremely inefficient, overly grandiose (and this was him thinking it) lifestyle. Oh, they had the bifrost machine, and other technological marvels – the Destroyer was proof of that, as were the occasional other odds and bobs that Tony ran across – but they didn't seem to have computers like humans did, for the storing of data. They didn't even have books. They had scrolls.

Unless there were actual computers, and he just couldn't find them. Tony wasn't even certain that he hadn't wandered into the children's section, or some sort of collection made for the equivalent of ninety-year-old grandmothers who thought that the internet was the work of the devil, because he couldn't read any of the damn things. Apparently, the Allspeech was extremely literal: it did nottranslate to the written form. Instead they used a script which, surprise surprise, looked very similar to Old Norse – a pitifully two-dimensional versions of the runes that made up the bifrost machine.

Tony was brilliant, he really was, but even he wasn't able to learn an entire language in a night – thankfully. He was pretty sure there were people who could do that, but they were the type of savants who had issues that made his issues look like a 250-word article: short and sweet. French, Italian, and Spanish were mixed up in his childhood, along with the Latin that his tutors had always pressed him to learn; German he'd picked up the first time he'd gone on a race-car-building spree. Japanese had taken him a couple of weeks of living in Tokyo, while Russian had been an ill-fated attempt to see if he was any better at literature analysis if he tried it in the original language of some of the finest masters of science fiction (answer: definitely not). Dari he'd picked up slowly, here and there, as the Middle East had moved from middling to high on the government's list of military threats. So sure, he could learn Asgardian, or whatever it was called – but it would take weeks. A far cry from the shortcut he'd been hoping for.

Even worse was the way the city seemed to be crumbling in on itself. He'd run across no one living, and the ruins seemed to be slowly but constantly collapsing in on themselves. The meagre light the stars provided was barely enough to see by – the arc reactor provided better light, but made him feel exposed, like a target in the dark – which he was.

JARVIS kept him appraised on the dropping external temperature, but the cold didn't seem to be helping slow the collapse – the ocean held too much salt to freeze just yet. Nor did the cold preserve anything else. He'd run across a few private chambers, occasionally with meals still left out. The food on the plates had already begun rotting, and was covered over with molds that died even as he watched. Likewise, the water was dark and toxic. A desalinization machine might make the ocean water drinkable – but he had no materials to fab the membranes.

He'd die of thirst within days.

There was simply no time to try to learn Old Norse. Desperately, he went back to his scans, projecting the results up against half-broken walls and letting his brain leap from thought to thought, drawing parallels and connections. After a while, the patterns seemed to burn themselves into his head, but they made no sense: he couldn't see any fundamental underlying structure that would make the runes mean anything. In conventional human computing, everything boiled down to zero or one, on or off, and that was the basic block from which everything else sprung – but there seemed to be no common denominator between the runes. Taken by themselves, they were meaningless.

He picked up Heimdallr's sword from where it had been sitting beside him and threw it at the wall in disgust. The wall fared poorly, and the sword clattered to a stop on the floor of the next room over. Even if he could repair the systems – if, if, if – he had no fucking clue where he was pointing the portal, anyway. It was hopeless, pointless – he'd be dead too soon, just one more corpse among all the rest.

"FUCK!" Tony shouted into the emptiness. The ruined hallways echoed it back to him, and then a few seconds later, his voice bounced back from the soot-coated mountains. There was no other noise, other than the constant, never-ending sound of water rushing forward, rushing over, drawing in every ruined building and dragging it down into the depths. He'd die of thirst, and then his body would drown. Tony fell to his knees and punched the ground, because after all this time, all that 'facing your fears' bullshit, all his attempts to get past it, past everything, he was going to drown. He was never going to get home to Pepper – Pepper might already be dead. Pepper, and Rhodey, and Steve; Happy; Natasha and Clint and even goddamned Fury – Thor was already dead, Tony had seen him die, seen his body be taken by the water.

He slumped forward and stared at the ground. Nothing came to him – no brilliant ideas, no genius. He was in over his head, and there was no way out that he could see.

"Fuck," he whispered, just to JARVIS and himself this time.

"Sir..." JARVIS said back, low and quiet and unsure. Oh, god, JARVIS. He was going to die and then JARVIS would be stuck with his corpse, and all the other corpses, completely alone. Unless the power ran out – unlikely, unless he used it up on purpose – or the universe imploded, JARVIS would be alone until he decided to shut himself down, the closest thing he had to suicide. Tony could do it now – shut him down – take the terrible burden from him –

"Sorry, kiddo," Tony mumbled to him. He couldn't do it – not yet. JARVIS didn't say anything. Maybe he'd given up, too – he had to know the odds, he'd have known them before Tony did. They sat there together in the dark, listening to the waves and the occasional crash and crack of ruins falling down.

Footsteps echoed through the broken library.

Tony roused himself long enough to check the sensory data that JARVIS was feeding him. Whoever it was, they were already dead, just as all the denizens of Helheim had been – thermal imaging confirmed that. They probably weren't even aware of his presence. The dead he'd met so far had been pretty wrapped up in their own issues, although he was willing to admit that his sample size wasn't statistically significant. He looked up, though, when the footsteps came close enough for the owner to be standing in the pool of light given off by the suit's reactor.

"Took me a while to find you," Steve said, smiling crookedly. "Sorry."

His hair was still the same blond as before, but his skin... his skin had gone pale, drained of all colour, and somehow it looked so much worse on Steve than it had on any of the others. His eyes were grey instead of blue, and though the waxy sheen of death had not yet settled entirely into his skin, Tony could see its beginnings.

Tony let himself curl inward and rest his head in his hands. And here he'd thought that Steve had escaped Loki – but he hadn't. Not in the end.

"I had to keep dodging this dragon," Steve said, gesturing to indicate the size of it. He joined Tony on the floor, settling in to sit next to him without any of his customary grace – had death stolen that from him, too? What else had it taken? Something essential, if he wasn't flipping out about the Níðhöggr. "It flies around snatching up corpses. You shouldn't just be sitting here in the dark, Tony, you make an excellent target. I caught sight of you miles away."

"It doesn't matter," Tony said quietly.

Steve looked at him sharply, and then set his jaw. When he spoke, it was with the measured air of someone who had come up with several possible answers and had to discard the first few as being over-emotional. "It matters to me."

"You're dead."

"Yeah. My friends – uh, they got my soul back into my body, but there was a fight, a battle..." Steve trailed off, shrugged. "I lost. It was a good cause. After, though – everything started collapsing. I think I was supposed to end up in some other realm, but it got squished into this one. That was how the women I met put it, anyway, and they looked like they'd know."

Tony stared listlessly at the wall. He was having a conversation with a corpse. He'd been having a lot of conversations with corpses, recently, which really ought to have been a clue that this was never going to end well. He wondered if the women that Steve had met were corpses, too – they probably were, if JARVIS hadn't picked up anything on the thermal imaging by now. Moving or not, everyone here was dead and soon to drown – him included.

"So. You got a plan to get yourself home?" Steve prodded, when Tony didn't say anything after a while. Tony shook his head, electing to remain mute. It was easier than trying to find the right words.

"You're just gonna sit in the dark, then. You're gonna give up," Steve challenged. "Come on, that's not like you. The man I know – he doesn't give up. He fights to the bitter end."

"This is the bitter end, Steve," Tony said dully.

"Not for you," Steve shot back emphatically. "Tony – I know I'm dead." He looked away for a minute, and when he went on, his voice was quieter. "I know because I've lost something. But you haven't. You can't give up. You can still get home – you can still make a difference."

Tony closed his eyes. "No, I can't. I don't have the time. Even if the dragon doesn't kill me, or drive me insane, in a couple days I'm gonna be dead of dehydration anyway."

"Then these are a pretty important couple of days for you, aren't they?"

Tony snorted. "The last time somebody said that to me, I actually had a breath of a chance. I've got nothing, Steve. I can't figure out how to rebuild a fourth of the bifrost system in a couple of days – I won't even be able to figure out where the technical manuals are in a couple days, if they even exist. I'm good. I'm a genius, I'm one of the smartest guys on Earth, or off of Earth, but some things are just impossible."

"I'd've thought you'd rather spend your last days figuring out what you could, rather than just sitting around here in the dark," Steve said, and if there had been the slightest note of disappointment in his voice, Tony would have punched him – even if he was dead. But when he looked over at Steve, there was only sincere compassion, and a deep earnestness. Steve – expected him to do better.Wanted him to do better. But Steve wasn't judging him for falling short of those expectations, and somehow, that cut him right down to the marrow, deeper than judgement ever had.

Tony huffed a laugh. "Yeah, you got a point there," he admitted, hauling himself to his feet and holding out a hand to Steve. Steve took it and let himself be hauled to his feet. He felt... oddly light, and Tony frowned. Everything was lighter in the suit, of course – if he hadn't had practice at the whole 'interaction without tactile feedback' thing from years of working in 3D holograms, he'd probably have broken everything he tried to pick up the first few times. But the suit's sensors confirmed: Steve's mass was barely 48% of what it should have been. At that mass he should have been – well, he was dead, but he should have looked like somebody who'd died from starvation, and maybe lost a limb besides. Tony closed his eyes before his brain could decide to start looking for whatever wound had killed Steve. He didn't want to know.

"Anything I can do to help?" Steve asked, with that same earnestness. The answer was... not a resounding 'no'. Even if this Steve had had years to get caught up to the future, unless he'd picked up a couple of doctorates in that time, he'd be useless for any of the technical stuff... but if his abilities matched Rogers', then he should have exceptional pattern recognition.

Tony pulled out his tiny screwdriver and sketched runes in the dirt covering the floor. The 3D runes that made up the bifrost weren't strictly layered – they were arranged more like a tangled knot of string than an onion. But there were occasional patterns and repetitions, things that seemed more important. If Asgardian organization was anything like human – which, from the evidence, it wasn't, but Tony had to start somewhere – then these patterns wouldn't be the subject of titles, but there would have to be scrolls containing them – if scrolls on such a topic existed. And if he could figure out what the overall structure was, he could interpolate a lot of the details. The runes that he sketched were the 2D versions, which lost variety and subtlety, but he'd take what he could get.

"See if you can find any patterns that look like these," he explained, as he sketched out a paragraph's worth of runes. "They're the important ones. And if you can find anything that's not in runes, anything readable, that would be cool, too."

"On it," Steve said, clapping him on the shoulder and going over to the shelves of scrolls. Tony watched him for a while out of the corner of his eye. Like he'd hoped, Steve didn't seem to take very long at all to scan each scroll, unrolling one as fast as he could before rerolling it and setting it aside – the best manual substitute for a search program Tony could have hoped for.

He went back to studying the scans. The structure still was baffling – it should have been a pretty sculpture, and no more. If this was the base level, then there was nothing connecting all the runes, no way for any of them to mean anything –

Hold on. Back up.

If. He'd thought that it was because the runes were nanostructures. Each was small enough that the fine details became hazy but while – Asgardian technology might be different, there was a point where you got so small and just couldn't go any smaller. So he'd assumed the runes were the base (because if they weren't, he was completely fucked on trying to repair it) – but clearly, they couldn't be. They made no sense without a background setup... which wasn't present.

Unless it was. Asgardians were pan-dimensional – why couldn't their technology be? And okay, that meant he might still be fucked in attempting to fix anything, unless that base – the hardware, then, while the portion he'd scanned was the software equivalent – hadn't taken as much damage.

"It's code," he said aloud. "It's – holy shit." The sheer size of the program was dizzying – larger than any human, even him, could hope to comprehend. What had it all been for? What did the bifrost machine need?

Power, obviously, but that was easy. Navigation would be a critical issue, especially given the implications by the Foster Theory that while the distance the traveller crosses would be much less, the distances the wormhole covered would be exponentially greater (and in a great many more dimensions) – and they'd need to be calculated down to the micrometre. Any variances above the tolerance level, and the wormhole would simply fail to open. But once the navigation was known, the bending of space time was – well, that had to be the actual hardware portion of the machine; the navigation code would have to include directions on the power allocation.

Generating the nav calculations in the short time that the bifrost took to open a wormhole would need the sort of processing power that maybe extremely advanced quantum computing could provide– but there'd been no sign of any sort of quantum computing that he'd seen. So, was that also 'elsewhere'... or did they simply store the pre-calculated numbers hard-copy? There were only limited places that they seemed to want to go – the bifrost didn't open up just anywhere, or they wouldn't have had to spend a couple hours hiking through Jǫtunheimr. But this was the 'central' universe, and even if Heimdallr had said that there weren't infinite universes connected to this one, they'd still have... a lot of data.

"Tony? You figured it out?" Steve asked, rolling up another scroll and putting it back on the shelf.

"Maybe," Tony said, as possibilities spooled out in his thoughts. If the bifrost program was mostly data, then he might not have a much to fix as he'd thought – if it had only been part of the 'hard drives' that had been destroyed, leaving the main program intact. If, if, if – but it had to be data. Tony had seen Selvig's program for calculating a wormhole, and while it had certainly been complex, for sheer size it had nothing on the amount of data it generated. Even with SHIELD's baby quantum computers working on it, it was years away from having finished its run for a single, fairly short wormhole – they'd been counting on breakthroughs in quantum computing to move up the finish date.

He reorganized the scans, trying to estimate how much data could be represented by the runes – more than could be represented in 2D, certainly, but there too few variations for each to be an individual word. If he could figure out what the data points looked like, then he could put together what a complete set of wormhole data looked like, and start eliminating them – and start figuring out where the actual program was stored.

Out of the corner of his eye, he saw the Níðhöggr's soar into view, one of its arcing wings visible through the gaps in the library's ruined walls. Was it bigger than it had been before, or merely closer? Impossible to tell, when its geometry shouldn't have been able to exist in the first place. The weight of wrongness overwhelmed him, crushed him to the floor and left him gasping for breath; he could feel his mind straining to comprehend how the wing could be a Cesario fractal but still smooth, still three-dimensional – or more –

"Tony? Tony, can you hear me?" He came back to himself to find Steve crouched over him, looking concerned. Of course the Níðhöggr wouldn't affect Steve – he was dead. Dead, and lacking... something.

"I'm fine," Tony grunted, pulling himself into a seated position. He felt like he should be sitting in a small crater, but he wasn't – he'd just fallen over, not even with any particular force. When Steve still looked worried, Tony offered a smile, and tried to let it come through in his voice as he said, "You were right. Sitting around, waiting for the end – not my style. This is... better."

Steve rested a hand on the armour's shoulder for a long moment, still looking worried, but when Tony just tilted his head innocently, Steve seemed to give in. "Okay," Steve allowed. "Just – let me know if I can do anything."

"Sure thing, Cap," Tony agreed, pulling himself back together and re-engaging in the brainstorming session with JARVIS. They argued over which segments of runes were important – and here was the benefit of working with someone who fundamentally thought differently; they could attack the problem from so many more directions than Tony could working alone. Occasionally Tony called Steve over and sketched out new sequences for him to find.

Until, finally, they hit pay dirt: Steve found a few partial fragments of what they'd been looking for, put together in more ordered ways.

"Bingo," Tony crowed, as JARVIS scanned the information and numbers appeared on the HUD display besides the runes – rough estimations for possible value ranges. Then it was simply a matter of cross-referencing and narrowing until they had, if not an understanding of the Asgardian written language, a rough idea of how their coordinates worked. It wasn't anything like any human system – either the scale didn't fully correspond to numbers, or their numerical system was ridiculously complex.

"Sir, the core program may be stored inside the crystal understructure, beyond the distance my scans can penetrate," JARVIS reminded Tony gently as he started grouping together data clusters, tagging them as individual wormholes. Thanks to the idiosyncrasies of the coordinates system, they were much larger than they should have been – were the Asgardians just being redundant, or was there something he was missing?

"Uh-huh," Tony said, pausing to think. "Bring up Selvig's stuff, will you?"

JARVIS was a bit pedantic about uploading relevant information to the mission, in case they got cut off from communications. He couldn't upload all of his resources, of course – JARVIS was spread out across various server farms, and there simply wasn't room in the suit. But there were things that it was good to have immediately on hand, and as Selvig's notes and papers – and, oh glory be, his programs – began to scroll across the HUD, Tony was reminded yet again of just how many times JARVIS' over-preparedness had saved his life.

"I live to serve," JARVIS said dryly. Oh. Had he said that aloud?

Well, his pedantry might even save them this time. Tony opened up a new document and had the HUD project a virtual workspace in front of him – with the suit matching his movements to the projection, he could type just as well as he could at an actual keyboard. The first thing he needed to do was get JARVIS to start an interpretation program, to try to figure out where the wormhole data sets were going – it would take too long to run, probably, but he had to try. Then he got started on Selvig's program, taking it to pieces and making it better, designing it to work with taking data from an Asgardian source. He could put it on the suit arc reactor's tiny little computer, hook the thing up to provide power... and he might actually be able to get somewhere.

Steve wandered back and sat down beside him at some point. After a minute, Tony looked over and saw that he was smiling. "Something up, Cap?" he asked casually.

"You look strange when you do that," Steve said, but he didn't sound mocking about it – well, maybe a little teasing, but it was friendly. Unexpectedly, this made guilt churn in Tony's stomach. Steve was... Steve was dead, just hanging around and trying to get Tony back home, even though it was completely futile. How would Steve want to spend his last days? "But we should get under better cover now that I've finished going through these scrolls. There're too many holes in these walls."

Tony blinked. "You've... gone through all of them?" he asked, then rolled his eyes at his own inanity. Steve wouldn't have said it if he hadn't. He scrambled to his feet, looking out over the ruined library – it wasn't enormous, compared to, well, everything else on Asgard, but it was still of Asgardian design, which meant it mandatorily pretty large. "You've – JARVIS, how long have we been at this?"

"Twenty-two hours, four minutes," JARVIS recited dutifully, before adding, with some hesitation, "Knowing the current circumstances, I assumed normal protocol did not apply and did not inform you of the twelve-hour mark."

"I – twenty-two hours?" Tony asked – wow, apparently he was just repeating everything today, where was his brain? Twenty-two hours might explain the stupidity, except –

- Tony didn't feel tired at all. He felt stiff, like he'd been hunched over in the same position for a couple of hours, but just standing was making the feeling fade. He didn't feel hungry, or thirsty – he didn't even feel caffeine-deprived, and that right there was fucked up, because he'd not had coffee in two days, he shouldn't have been able to go for twenty-two hours without starting to flag –

"Tony?" Steve asked, looking at him in concern. "Are you okay?"

"I – " He broke off, putting one hand to the arc reactor. Loki's words floated through his mind: You will wander the ruins, eternal. You will know that you did this.

Shit. What had Loki done to him?

He swallowed, hard. "I'm fine, Cap. Let's get out of here."

"You're clearly not fine," Steve argued, even as he turned and started heading for the door. Tony detoured, briefly, to nab Heimdall's sword from where he'd thrown it. Although it was just as dark as it hard been in the library – which was to say, Tony's arc reactor was the only source of light – Steve led the way with unerring accuracy. Tony wondered if it was the supersoldier serum lending him enhanced eyesight, or – considering that he'd managed to navigate the darkness outside – some sort of thing you got when you died.

Which apparently wasn't something that was going to happen to him as long as he remained here. Shit. He didn't even know why he wasn't happy about this – he needed more time, to be able to repair the bifrost. Even if the programming was entirely intact, the repairs to the outer shell would take a while, given the machining problems alone. If he couldn't figure out how to use the sword (and that seemed likely, if it was also some pan-dimensional thing; scans hadn't come up with anything that would set it apart as remarkable, not even any runes) then he'd need to write an interface that could also play nice with Asgardian programs when he still only had a rough grasp of their coordinate systems. Machining anything was going to be a problem, if everything kept crumbling around them –

"Don't you want to go back home?" he asked, abruptly, instead of answering Steve's question.

"I'm dead," Steve answered easily. He seemed... remarkably at peace with that, Tony thought, staring at him. Or maybe it wasn't that – it wasn't peace, it was blankness. He just didn't care. Had that been what he'd meant when he'd said he'd lost something – the concerns of the living? But then why was he still hanging around Tony? "Here, this is the room I found when I scouted earlier. Solid walls, no lines of sight – "

"You went scouting earlier?"

Steve frowned at him. "I told you I was. You said you were fine and told me to go ahead."

He had? One of those types of conversations, then. Really, why did people always assume that just because his mouth was engaged, his brain cared at all about what they were saying? Especially people who presumably knew what he was like when presented with an engineering problem. "Uh, so I guess your version of Tony doesn't do the whole 'lalala-sure-I'm-listening' thing," he said sheepishly.

"If I'd known that you were that zoned out, I wouldn't have left you alone," Steve said. The frowny-face hadn't disappeared. "But I thought I'd better find something before you fell over. You're going to need sleep at some point, especially with no food or water – "

"Uh." Tony looked down and away, studying the walls of the room that Steve had found. It was a picture of opulent ruin – the walls might be stable, but the tapestries looked as if they'd been set upon by a horde of locusts. Or was that termites? What ate tapestries, anyway? "About that. I – don't actually need sleep. Or food, apparently. Loki did something to me, I dunno what."

Steve stared at him. "Put the faceplate up," he demanded, and the moment Tony complied, Steve set a hand against his forehead – a hand cold enough that Tony jerked away immediately. The feeling of dead flesh against his skin made him grimace, but he masterfully held back from gagging.

If he noticed – and he probably had – Steve didn't say anything. Tony didn't know if this was because Steve was being kind to Tony or to himself. It was probably a mix of both, he supposed. "You're too warm to be dead," Steve asserted a moment later, and Tony blinked. The thought hadn't even occurred to him. "And you still have colour." He gestured at Tony's face with the hand that he'd used to check his temperature.

How Steve could see colour by the shallow blue glow of the arc reactor was – totally not a mystery. Or maybe Tony just couldn't see any colour because there was none to be had; Steve himself was washed-out and pale. "I think JARVIS would have noticed if I was dead," Tony objected half-heartedly. Steve rolled his eyes, likely catching that Tony hadn't specified whether he would have noticed. That's what he had JARVIS for, after all – social security number, blood alcohol content, metaphysical state; JARVIS was good for everything.

"Indeed, sir," JARVIS murmured in his ear.

"Next time I'll be sure to shake you to make sure you're listening to me," Steve said dryly. The frown was beginning to clear up, though, so Tony counted it a victory. Steve wandered away into the dark – when Tony flipped the faceplate down, he could again follow his movements again on the HUD; apparently, he was inspecting the half-eaten tapestries. "It's probably a good idea to be under cover anyway. I saw that dragon again when I went scouting – I think it's gotten bigger."

"If it keeps eating corpses, I guess it would," Tony said. The words sat sourly in his mouth, and he pulled up status updates on the codes he had running. JARVIS had – Tony took a closer look. "Oh, well done," he murmured approvingly. JARVIS had cracked Asgardian numbers – it wasn't that the numerical system was complex, it was that their way of expressing it was the mostinefficient possible. Seriously, numbers were numbers, Tony loved numbers, but they didn't need odes written to each and every one – and either the Asgardians were doing that, or they were writing out words as numbers and storing those in their coordinate systems. It was like a GPS system that claimed that someone was should turn left at thirty-six point two nine latitude and fifty-two point eight four longitude, except in eleven dimensions to ten significant figures on a route nearly as fractured as the Níðhöggr's spine should have been. Did they not have numerals?

No wonder they needed so much storage space, such huge computational engines, if all of their data was like this, all of their numbers, even the ones they were using in calculations – Jesus, what a waste of time and energy.

"Asgardians like to be formal," Steve said. Tony hadn't meant to say that aloud, but, well, he didn't care if Steve heard, anyway. "I'm glad you've got a lead."

"Uh-huh," Tony muttered. "It just means – it means I fix the thing well enough to run it, and I've got a list of directions. No idea what's actually at any of the locations they lead to – all the directions are relative to here, and I've got fuck-all as far as where 'here' is." He waved a gauntleted hand expansively – although given Asgard's current state, maybe he should use some smaller gesture. "And that's if those places are still where they were – if you're right about worlds collapsing in on themselves... there might not be anywhere to go."

The armour's voice protocols wouldn't let Steve hear how dry his throat was as he said that. Dying here, in this wreck of a realm, was frightening. Being stuck here forever...

Once upon a time, he'd thought that immortality might be nice. To be fair, he'd been dying at the time.

"Hey. You'll get it," Steve said, abandoning his perusal of the tapestries to come back over and clap a hand on Tony's shoulder. It was just as ridiculous as it had been when they'd still been in Helheim, and Steve hadn't been able to stop being so touchy-feely all the time. But this time, it wasn't strange. It was just... reassuring.

"Of course I will, I'm Tony Stark," he scoffed, letting his arrogance buoy him. But it didn't hold up much longer than the quip, and he swallowed, hard. This was Afghanistan all over again, desperately trying to work out the miniaturized arc reactor equations in his head even as he was already throwing together a prototype, because he had to do something. Invention was never a guaranteed end-game, not then and not now – he'd discarded too many ideas over the years to be unaware of that.

"Well," said Steve slowly, "We could ask those women I met earlier. They seemed to know about what was happening to the worlds."

Tony looked up sharply. How had he not caught that? He'd heard what Steve had said but had focused on the irrelevant part, the biological state of the women, and not the importance of what they had said. See, this was why despair was a bad look for him – it made him stupid. "That is – that is an excellent idea. You think you can find them again?"

"They can't have gone too far, and you can fly." Steve shrugged. "I don't think going out there is a good idea, not with that dragon flying around, but if we need their help..."

"Point me in the right direction, then," Tony said, heading for the door. His footfalls felt lighter than they had since before Asgard died. "I'll try to avoid irritating your mother-hen instincts by staying out too long after curfew."

"Splitting up is still a bad idea." Steve shook his head. "I'm coming with you."

Tony made a face, hidden behind the helmet's mask. "Uh, how? Unless you've learned to fly. Bit awkward for me to be carrying you – you're a bit big for a damsel in distress, and carrying you around by the scruff won't exactly be comfortable for anything longer than a boost."

"You give me lifts all the time," Steve said, not breaking stride. "My version of you, I mean. I'll show you."

Despite Tony's predictions, it was not completely terrible. Steve stepped onto Tony's foot, wrapped an arm around his neck, hanging over his shoulders, and he wrapped an arm around Steve's waist to keep him secure – leaving him readily available to catch Steve if he fell. When Tony tilted forward for horizontal flight, Steve flipped around him and onto Tony's back (and wasn't it just lucky that the back jet-suit repulsors disengaged), clinging to his neck and leaving both of Tony's hands free for flight stabilization.

It was still incredibly awkward. Flying with a heavy, lop-sided weight took some getting used to – Tony nearly crashed them into a nearby wall the first time they tried the 'going horizontal' manoeuvre. Nor could he fly at anywhere near the supersonic speeds that he was used to; Steve could take a lot more punishment than any normal human, but he didn't even have a helmet, for Christ's sake. And Tony didn't want to test the limits of his limpet-ness.

Also, he was essentially giving Steve a horizontal piggy-back ride, and that was never going to be not awkward, ever.

Fortunately, as they rose above the ruins of the palace, Steve pointed at a beacon – a bonfire, far off in the distance. "That was the direction I came from. That could be them." He didn't bother to shout – apparently he knew full well that even in full flight, the armour's audio could easily pick up what he was saying.

The long-range sensors resolved the scene. Three women stood about the fire, their heat signatures so closely blended with the surroundings that the HUD barely picked them up in IR. More dead people; great. The visible spectrum showed that they were young – or had been – and were no more recently deceased than Steve. In life they might have been intimidating, with vibrancy and youth and, oh, being two and a half metres tall – but death had diminished that.

"Hold tight, cowboy," Tony said, adjusting the output audio volume upward, because Steve didn't have the benefit of sensors – a crying shame, sensors were awesome. He took off toward the distant firelight, his whole body thrumming with tension. Back out in the open, the threat of the Níðhöggr weighed down on him; it was a relief that the flight wasn't longer. When they drew nearer to the fire, the women looked up at them, but didn't seem surprised.

"Welcome to our fire, Captain, Man of Iron," the middle woman spoke as Tony drifted gently toward the ground. Her voice was deep for a woman – on the same register as Cate Blanchett's, lovely lady that she was. "We bring you tidings, at the end of the world."

Steve flipped around so that he could jump off, hitting the ground in a roll that, while economic, lacked the grace of the living. Tony was just glad that when he landed, he didn't have to worry about a passenger.

"You built the fire to signal us?" Steve asked. "Put it out. You'll bring the dragon." His tone had slipped into 'Captain America', more commanding and earnest than ought be possible – but unlike Rogers, it didn't have the note of fake bravado in it, revealing to any who cared to listen how uncomfortable and out of place the man really was. Steve had grown into his skin – or maybe it was just another side-effect of dying.

"The Níðhöggr will ignore us for now. We have magic enough left for that, if naught else," said the woman on the left. Her hair was as dark as midnight – the Arwen to Blanchett's Galadriel... if Galadriel had been a brunette. Her input wasn't reassuring. Nothing relating to the Níðhöggr could be reassuring. "We must speak with you, man of iron."

"If you tell me no man born of woman can kill me, I'm gonna say a) I'm not testing that, and b) Denmark sucks," Tony said flatly. He was tempted to aim a gauntlet at them, but he was pretty sure Steve would disapprove. "Boring, shitty climate – "

"Enough. Our time grows short," Blanchett cut him of.

"What's the rush?" Steve said. "You didn't seem in a hurry when we spoke before." Tony knew without looking at him that his eyes were narrowed in suspicion, even though his delivery was dead-pan.

"At that junction we still believed that the Tree of Life could be saved," the last woman finally spoke. Her hair was the lightest of the three's. Was he just imagining things, or could he see stars glimmering from her hair, as well? Was that why it was still light? "T'was our task to bring water from the Well of Urðr and pour it over Yggdrasil, that its branches might stay free of rot. But upon our return to the Well, we found it poisoned."

"Without its water, Yggdrasil will soon wither and die," said Arwen.

"So you see, the dead have no more time on this world than the few living, Captain," finished Blanchett.

The way they spoke - "You're the Fates," said Tony, then, "Wait, no, that's Greek. Uh. The norse equivalent." He supposed he ought to be grateful for that – weren't the Fates the ones who passed around an eyeball like a talking stick?

"We are the norns, yes," Blanchett confirmed.

"Or we were," noted her fair-haired sister – or were they sisters? Was that still Greek? "We determined the course of the tapestry that bound all lives, all realms, all fates together."

Tony snorted. He couldn't help himself. "Jesus. You were right, Steve. Fucking magic. Intent. You're why I didn't die in Helheim."

"It was our law that saved you then." Blondie's lips curled into a cold smile.

"As it is the remnant of our law that now tethers you to the ground. But our power is quickly fading. And we are reduced to begging the lynchpin of the Tree's destruction to be its saviour." Blanchett looked straight at Tony as she said this, her eyes seeming to pierce straight through the suit's faceplate and peer into his soul. Tony felt his blood chill.

"Tony didn't cause this," Steve said immediately.

Tony felt a rush of warm gratitude toward him – but it wasn't enough to chase away the cold that spread through him when Blondie said, "Stark did not cause this, but he was the cause: the instrument of Loki. In his youth, when his fate became known to him, Loki cast a spell reaching far and wide for a knife that he could use to cut through our web, the tapestry that binds all lives and realities together. After much time and toil, his spell brought him you, Man of Iron – from a realm so far that even we know it not; its fate is not ours to design, and as you come from outside of our power, so may you be used to break it. Hel saw this, when you landed at her feet, and attempted to destroy you – but she, like all of the guardians of the dead, may not destroy the unwilling lest she grow too powerful. Thus we decreed – and thus we doomed ourselves."

"She lied," Tony said. "She said - it was a favour – "

"She was the daughter of a liar, if not so mad as he. Once you were here," Blondie went on, "and he had confirmed your origin, Loki used your presence to poison the Well, weaving a spell to break the threads of our tapestry and turn them to follow your own myths. In doing so, he freed himself from the existence he should have had – and doomed all else."

"So all this," Tony gestured helplessly. "It all – I – " his voice broke off. He couldn't continue.

"Out of an infinite number of worlds, you were vulnerable at the instant Loki cast his spell," she said softly. "We knew not why, until we saw you, but it is plainly written upon your soul: you fell. He caught you."

Tony closed his eyes. This wasn't – he couldn't – oh, God. He'd tried to save Manhattan. He'd tried to keep Pepper safe. He'd knowingly committed genocide, but that had been against the Chitauri, that hadn't been – he hadn't meant –

No. Nononono – he hadn't meant to destroy thousands of lives with his weapons, weapons in the wrong hands, but that didn't matter – what mattered was that he'd done it. This was all on him.

All of it.

"With Yggdrasil dead, all life, all of the universe, shall soon cease," Arwen picked up where Blondie had left off. "As this place sits at the heart of all others, it will pull in all of the other realms we have woven, and consume them. Those further out may have more time – but they will fall into the decay in the end."

Steve was the one to ask the obvious question. Tony still couldn't speak. "Can it be stopped?"

"It may be possible," Arwen allowed. "If the cycle of Ragnarok can be completed, before the Níðhöggr swallows all that remains of these realms, and moves on to other prey."

"Tell me how to stop him," Tony said. His throat felt as dry as dust.

"Loki wanders now beyond our ken," Blanchett said darkly. "For all that he brought about doom to these realms, he has escaped beyond even them. Perhaps he is now in a place such as your own realm, Stark, there to bring about yet more destruction."

"If Loki is slain, Ragnarok may yet complete," Arwen said, with a hint of cruelty as black as her hair.

Steve was frowning. "He's – like you – a pan-dimensional alien. There're multiple copies of him – a lot of copies. How are we supposed to kill someone like that – do we have to track down every last one of him?"

Ideas rose in Tony's mind, algorithms and windows into other worlds and methods of improved efficiency – but Arwen had a different idea. "That will not be necessary. Like the serpent he birthed, Loki is more easily killed than that – cut off the head, and the body will die."

"Kill the brain, the him from this realm," Tony muttered. Other ideas spun out feverishly from that starting point. He'd done this – he had to fix this. Failure was not an option, not when there was so much more than his own life at stake – there was everything at stake. "Okay, then how do I find him?"

Blanchett shook her head. "We do not know."

"Loki's always had a taste for the personal," Steve put in, his eyes troubled. "He'll start on your world."

"Then how do I get home?" Tony demanded of the norns.

"We do not know," Blanchett said again, and Tony wanted to curse them, except that the irony of cursing the fates might actually have been enough to kill him. "Your world lies beyond our sight." The one answer he needed most and they didn't have it. It fucking figured.

"Our time has ended," Blondie said, and for a moment he thought that she was just giving another excuse, before he noticed identical looks of alarm on all their faces. Alarm muted by death, but alarm all the same.

"The Níðhöggr is coming," whispered Arwen.

"Go," said Blanchett.

Tony screwed his eyes shut – he wanted to curse them even more, now. Steve had already wrapped an arm about him, reading to be carried – he was completely willing to abandon the three women, and that. That wasn't Captain America. That was wrong. Even the women cared, at least the tiniest amount – or did they only care about their creation being unraveled? What did you lose when you died – what had Steve lost?

"Tony, they're already dead. We have to go – you can't even stand the sight of that thing, you can't fight it!" Steve said, but it wasn't logic that made Tony take off. It was fear. The bubbling pit of self-hate that he kept locked in the back of his mind grew just a bit larger – but it wasn't enough to make him go back.

There were three solid walls between him and the Níðhöggr by the time its enormous maw finally appeared, only for an instant before it vanished again, but Tony saw it anyway. What use were walls against the physically impossible? Its head was the size of a small hill; he couldn't see them, but he imagined the norns falling into its gaping mouth, resigned and afraid all at once. Tony shut his eyes and prayed to a god he didn't believe in while Steve hovered over him, looking worried. Looking dead.

"You need to fix the bifrost and find a destination," Steve said grimly.

"Help me up," Tony mumbled, tottering away once he was on his feet again. He grimaced and stiffened his resolve, then in turn used that to stiffen his limbs. This was all on him. He had to fix it – but fuck, he was an engineer. Fixing things? Not a new concept for him. "We need to fly out to the bifrost machine. I need more scans."

Out at the edge of the world, it was easy for time to begin blurring together. Tony's thoughts were a mess – scanning, deciphering, and programming, his body sitting on the slanted floor of the bifrost machine while Steve prowled about and stared out at the dying universe. At some point, the runes began to make more sense than they should have, and he vaguely began to get the idea that he ought to take a break – but what was the point? He didn't need to eat, or sleep – he didn't even need to shave. He dismantled the central column and bits of the suit, scavenging bits of internal circuitry as he built a control panel that he could actually use – because fuck pan-dimensional control systems anyway; Heimdall might have been fine with only his sword, but there was nothing special about the weapon in the three dimensions that Tony could see.

He made sure to put the armour back together afterward. It was the only protection that he had on those occasions when one of the Níðhöggr's wingtips stretched out into the sky and fractals broke in his brain and he had to hide from the sight behind Steve.

But for all that he could rip non-essential panelling off of the walls, cut them up with the suit's lasers, burn in new circuitry and weld them over the gap – the navigation problem eluded him. He could translate the coordinates into something understandable but they were all relative to Asgard, this Asgard, and he had no idea where this Asgard was. Even translating the coordinates was taking a stupid amount of time – and they were organized like a three-year-old decided to play fifty-two pickup with a million-card deck. Asgardian science might be cool, but their engineering sucked.

"I'm not looking for my Earth," Tony said at one point, when Steve had asked him something – he wasn't sure what. Quite possibly Steve had been asking Tony his opinion on Mets vs. Yankees, but he hadn't been paying attention. Steve talked a lot – Tony knew he was poor company, too much wrapped up in the math and the symbols and how they'd started to become one and the same. "Heimdall said they don't have it. I'm looking for any place that might get me a bit closer – figuratively speaking." He finished with his current plate – the eighth of nine – and left its edges to cool, pulling up his calculations while he waited – once it was cold, he'd need to do some detailed work on it before he could attach the last layer.

Steve made encouraging noises, so Tony kept talking. "He talked about a cluster of realms – I want to get to the edge of that cluster, closer to whichever cluster my world belongs to, and see if we can hop over the border from there. Portal technology can't be all that common, but we know that the Asgardians aren't the only ones with it. Or just general dimension-breaching tech." He vaguely remembered Steve talking about someone named Reed Richards and a series of highly implausible adventures.

The algorithms he'd been trying out came up with nothing – another set of dead ends in his attempt to narrowing down his direction. He slumped, wanting to rub at his eyes – but the armour would make that gesture impossible, and he was always in the armour, now. Disgusting – but less so than he would have thought; apparently immortal stasis strong enough to stop his beard from growing also stopped him from becoming a mess of ew. Fortunate, because it wasn't like he could take the armour off – with the light had gone all of the heat.

With the algorithms abandoned his brain turned more of its attention outward, enough to understand Steve when he said, "I think time's being weird, like it was before." The urge rub at his eyes increased.

"Not the best person to be ask," he said instead. "There's no coffee – how do you expect me to be able to remember what day it is?" What did it matter, anyway, when there was no calendar? He hadn't asked JARVIS how long it had been for a while, instead marking the progression of time by watching Steve's skin steadily grow more corpse-like – despite how much he wanted to not notice. He wondered what Fury would think when he returned from another world with a zombie Captain America – that would be a reaction well worth watching.

"I think that's why it is going weird," Steve said wryly. He looked – happy? Relieved? When had Tony last said something that made any sense to him? "When you don't notice it passing, it slips away."

"Trite," Tony muttered. He couldn't concern himself with the vagaries of time in a collapsing universe – not until they started fucking with his calculations. He just couldn't. It was a puzzle, anawesome puzzle, but it was not one that he had time to investigate.

The eighth plate had cooled. He started on the circuitry, tuning out Steve once again, and the world vanished in a haze of metals and math. The circuitry grew, mirroring what he'd seen when he'd carefully dismantled the panelling on the opposite side. God bless Asgardians and their need to use exotic metals and rare materials on everything, even mere decoration – without the proper materials, this would have been impossible.

It still might be. Tony's world snapped back into focus as Steve's hand closed about his, making him yelp. The wrist lasers disengaged with little more than a thought, but still – "Shit, Steve, what the hell? Those could take your hand off wi – "

The Níðhöggr's tail lashed around the side of the world, past the now-silent waterfall, and slammed into the frozen sea. The sounds of ice breaking were discordant notes, destructive interference that amplified, triads that couldn't harmonize, a soprano singing base; a crack ran through the sea where the tail fell, all the way from the edge of the world up to the mainland – which was now much more distant than it had been. So much of the world had sunk beneath the waves, before they'd frozen from the cold. The tail scraped sideways and away, curving about once before it vanished beneath the rim of the world.

Tony came back to himself huddled over, Steve cradling him. "Sorry, sorry," Steve was saying softly. "I was looking over the edge and I saw it, but you didn't hear me. I didn't realize it had gotten that big – it's definitely growing."

"Nnfgh," Tony mumbled, trying to uncurl and stand up.

Steve had to help him to his feet, and then steady him. "You need to find a destination," he said, when Tony could finally stand on his own again.

"I've been trying!" Tony protested. His brain felt like soggy bread, like it had gotten whacked with the tail as well.

"Can't you just use the location that's furthest out?"

"That is an extremely shitty idea – that could be the opposite side of where we need to be!" Not that the coordinates translated very well into a linear vision of the universe, but that didn't mean that they couldn't end up further away than they'd started.

He'd nearly finished the circuitry before the Níðhöggr had appeared; now he went back to it with a renewed fervour. Some part of his brain acknowledged Steve trying to talk to him, but he didn't answer, too busy with new calculations, new proofs and algorithms to try to narrow down the navigation. The ninth plate was welded into place – easy – and he stepped back, satisfied.

It still didn't solve his biggest problem. He had no clue which set of coordinates to pick – if any of them.

"I don't think you've got time to figure it out," Steve said grimly. His eyes were distant, filmed with congealed death.

"What – "

The long neck of the Níðhöggr lifted above the mountains that had hidden it, and it was easily as large as them. Tony didn't know if he dropped the tools he'd been holding – he didn't know if he'd accidentally activated the hand lasers and hacked the bifrost machine in half. He was too busy trying to claw his eyes out – he fumbled for the suit releases, but JARVIS overrode him, locked everything into place, keeping the helmet on – there was thunder, the sound of annihilation, as the maw snaked forward and slammed into a mountain side, chewing through it with terrifying speed.

The terrible curve disappeared again behind the remaining mountains, its movements choppy and sinuous – it was breaking the space-time about it. No, not space-time – he'd have to call it something else. Foster hadn't given it a good name, had referred to it in boring terms that were easily forgotten, too interchangeable among theories about anything from the structure of the universe to economic reform. For such a creative scientist, her writing had an exceptionally dull vocabulary – perhaps because she was all too aware of the outlandishness of her ideas.

"Tony." Somebody was saying his name – Steve.

Steve was bent over him; his fingers felt behind Tony's neck and hit the release catch there. The faceplate opened for him - "JARVIS, you traitor," Tony mumbled, his breath frosting in the freezing air.

"You can't keep doing this," Steve said, voice grim and eyes worried. Those baby-blues were very good at conveying worry – disconcertingly so. "That thing's gotten too big – there's not going to be anywhere to hide from it. You have to pick a destination."

"If I pick the wrong one – "

" – then at least you'll be alive and sane. Tony, you have to go."

"Shit," Tony said, because it wasn't like he could argue with that. So far – so far he'd been lucky. He'd caught glimpses of the Níðhöggr, the curve of its spine, its tail; teeth and impossible wings; but if he stayed – the thought of seeing the thing in its entirety made his blood run cold. Even the idea was paralyzing, so badly that if he hadn't been trapped in the suit, he'd have been shaking.

"Okay, okay," he said, snapping down the faceplate and turning his tools on himself. "JARVIS, I'll wake you on the flip side." The arc reactor in his chest could power the suit – but it would be folly to leave it connected to the suit for the trip. Maybe the bifrost would drain it anyway, but if the drain had been due to exposure to the outside of the suit, then leaving it disconnected would give him access to a power source wherever they ended up.

It was the work of moments to remove the suit's arc reactor and disconnect the backup cables from the one in his chest – it took more time to cross the slanted floor of the bifrost; without power, without the suit's auto-balance, navigation on such an uneven surface was considerably more difficult. He kept expecting to slide downward, even with Steve hovering about, ready to catch him at any moment. "Just let me – " the arc reactor clicked into place.

The bifrost machine lit up. Sparks flashed at some of the welds – minute debris being dislodged by the power now running through them – but all of his repairs held, and nothing that he'd missed exploded. He let his breath out, and set it to aim at the furthest out set of coordinates that he'd translated. If he was going to gamble, he might as well gamble big.

"Right. Okay. After I hit this button, we need to stand in front of the entrance," he pointed.

"Tony." Steve shook his head. "I'm not going."

"What?" Tony blinked at him. His hand fumbled out and he hit the disconnect; power died. No sense wasting energy – he did not want to have to build another particle accelerator. "Of course you're coming."

"I'm dead."

"That is a complete non-sequitur! So what?" Who cared if he'd lost something in death or not – he was still walking around and talking, he could come along and be dead somewhere else.

"I'm dead and my home is dead. You came from somewhere outside this – someplace I can't go. You need to get home and keep your people alive," Steve said, and it sounded like an order.

Fuck that. "Fuck that," Tony said. "Like hell I'm going to – "

"You have to," Steve insisted, and the expression on his face was the exact same one that Yinsen had worn as he died. What was it that Phil had said, weeks, months ago? Conviction. "I don't exist in your world. I can't."

"You don't know that," Tony protested weakly. He was selfish, so selfish – he couldn't do this alone.

Steve overrode him again, his voice more gentle this time. "Yeah, I do."

"No. I killed you – it was my fault. I can't just leave you here. This world is hell, Steve."

Steve stepped forward, hitting the release for the faceplate and flipping it up. "It's not so bad from my perspective, Tony. But you're alive – of course it's wrong to you. And that's why you need to go." He leaned forward and kissed Tony, briefly, mouth closed – although even that was enough to make Tony's skin crawl. He wished he could have taken comfort in it instead. Steve must have felt Tony shudder, because he stepped back quickly, flicking the faceplate down again before Tony could start developing frostbite. "See?"

"It's my fault you're dead," Tony said quietly, because after all he had done – or what another version of him had done; what did it matter, when that version was so obviously so close? When Steve had stepped in to kiss him – he couldn't abandon Steve. Not like this.

"It wasn't you – "

"It might as well have been me!" he cut Steve off, his voice raising. "It could have been me!"

"It wasn't," Steve insisted. "These are alternate worlds – in another world I killed you – in another world you were a woman and we got married instead." Wait, Tony had time to think, why had hebeen the woman? Well, there was almost certainly another universe out there where it was the other way around, too. "It doesn't matter, Tony – even in my world, it wasn't your fault. You weren't involved. I know that now."

"But you're dead anyway!"

"Yes, I am," Steve said, oh-so-gently. "And I'm asking you – as a last request – to go. You have to get back to your home. You have to save them from whatever this is." He gestured out the far exit, at the enormous darkness that was all that remained of Asgard. There were so few stars in the night sky, now, that it was difficult to discern where the sky ended and the ruins began. "You believed those women. Loki isn't gonna stop here, and I don't think that dragon will either. If your world is still out there, you need to save it, and you can't do that if that thing drives you crazy first."

Tony bowed his head. Damn Steve, anyway – he wanted to just grab the man and hit the switch, but in the unpowered armour he had no chance of forcing Steve anywhere he didn't want to go. And he had people back home – Pepper, most of all, but there was Rhodey and Happy and an entire world full of people that didn't know that a reality-devouring dragon from legend and a pan-dimensional alien god were looking to commit... what? Pull a Davros? He didn't know – but it would end in death and darkness. He had to stop it.

"You're an annoying, suicidal prick," he said viciously, blinking perhaps a tad more often than normal.

"Can't be suicidal if I'm already dead," Steve said with an odd mix of grimness and cheerfulness. He pulled Tony into a hug, and Tony couldn't resist clinging on, even though he was grateful for the armour and helmet, keeping him from coming into contact with Steve's bare, dead skin. He would have clung on for longer – but then Steve was stepping back and directing him to stand over to the entrance. He must have been watching when Tony had connected it before, because there was no hesitation in his movements as he pushed the arc reactor back into place. Power flowed back into the bifrost and the walls hummed.

"I just press this button, right?"

"Yeah," Tony said. His throat was dry, but he had to try, one more time – "Please. Steve. Come with?"

"Sorry, Tony," Steve said, smiling a little – maybe at the absurdity of it all. He flicked the activation switch. "Good luck. And just so you know – " Rainbow energy was gathering about Tony, now, bright enough that it made him squint; he couldn't see Steve any more. " – even if you screw up – I love you. Always."

The bifrost beam roared and hurtled him out into the dark. It wasn't any better with the armour protecting him – he felt just as exposed, just as vulnerable. The kickstarting energy from the arc reactor pulled the wormhole to life, but as he'd calculated, most of the power came from someplace else – and there was enough energy around him to rip him apart. The fact that it was ripping space apart instead was not at all reassuring.

The distance was so far that he shouldn't have been able to see anything when he looked back, but he did anyway – and immediately wished he hadn't. The Níðhögg's terrible form swam out from behind Asgard, now of a size with the ruined world, although he knew it wasn't, it wasn't. Looking at it full-on was like staring at two contradicting mathematical proofs, ones that he had complete understanding of; the contradiction was not a mistake, it was because logic itself was breaking down. The underpinnings of reality were no longer valid – reality was being eaten, swallowed whole –

The Níðhöggr's teeth closed about Asgard. Tony couldn't look away: his body was frozen, locked silent and still, and he couldn't scream anywhere except in the very back of his mind. Nothing remained between him and the Níðhöggr; he could see all of it, and it was impossible, and glorious, and ohgodpleaseno. This was a sight that had driven a god mad, driven him to kill and laugh and lie and all these things were true about Tony, all these things, he didn't want to be Loki, IamnotLokiPLEASE–

The bifrost machine disintegrated as the maw crunched shut. About him, the rainbow of light exploded into fire: purple, blue, red, infrared, ultraviolet, microwave, x-ray, radio, gamma, gamma, gammagammagamma. Spectrums he shouldn't have been able to see, but he could, just like he could see the Níðhöggr, the Impossible Thing, could picture it and see how it all fit together. Fire roared all about him, burning up the wreckage of Yggdrasil for fuel, as the bifrost lost its hold on him and he fell.

Something whispered in the back of his head, and Tony wasn't sure if it was him or not, wasn't sure if his mind had finally broken, no longer knew what his own thoughts sounded like. But the message stayed with him as the flames burned redder, hotter, roasting him alive inside the suit. He couldn't breathe; the heat pressed in on him like the Níðhöggr's jaws, everywhere and nowhere, fire and ice. The last splinters of the World Tree burned to nothing and the spectrums of the flames compacted until they fit neatly within a two hundred nanometre spread, only red and orange and nothing else –

Remember, the voice said, and then mercifully everything stopped.

The world roared.

Tony's eyes snapped open as he gasped for breath. Right in front of him there was – blue, bright blue, so bright that after a half-life in darkness it seemed blinding – blinding and brilliant andwonderful. There was blue and – green? And blond, and that was – that was Steve.

The Hulk – it was the Hulk roaring, not the world, Tony realized, as he roared again. There was Steve – the original one, Rogers-Steve, not Steve-Steve – not yet, at least. Thor was there, too, and they were both blond and colourful and alive – "What the hell?" Tony wheezed.

His first thought was to ask JARVIS, but of course there was no power, and for some reason the faceplate of the suit had been torn away – he could feel the rest of the helmet, though, what hadhappened? Where was he? Rogers was still looking down at him, but the expression on his face – that was Steve's expression, one that Rogers had never worn, not when he was looking at Tony. It was fond, relieved -

"What just happened? Please tell me nobody kissed me," Tony blurted out. The feeling of Steve's dead lips touching his own lingered, and the smell of the frozen saltwater sea washed over him again, frost and decay mingling together. Steve, Steve, Steve – oh, god, he'd left Steve behind. Why the hell had he done that? He should have dragged him along, he should have come up with a way to force Steve to come, he should have -

He should have kissed him back. Pepper would have understood.

The air here smelled like dust. Tony's eyes skittered around, gathering data. Steve was covered in sweat and grime, Thor looked... like he might have a hair out of place, okay, and Hulk still looked triumphant. Those were Chitauri bodies over there – was this the same day as the attack? What the fuck had happened? Asgard had definitely not been a hallucination; Tony had hallucinated before, he dreamed math all the time, but the universe dying around him – that hadn't come out of his own head.

Scans. A simple x-ray could confirm it – unless Loki had been lying when he said he'd removed the shrapnel.

"We won," Steve said – Rogers said. Tony made himself relax, exaggeratedly – neither of the spies were nearby, he didn't have to worry about somebody reading his body language perfectly. Steve could have – but Steve was gone, left behind on a world consumed by that... thing.

Rogers' words should have felt like a benediction. They'd won – this battle. But whatever else had happened, whatever he'd seen...

It was on the tip of his tongue to say something. But Steve wasn't here – and if Rogers was a close match, he was still too different. Even worse, Thor – member-of-a-race-of-pan-dimensional-aliens Thor, more-like-a-finger-than-a-brain Thor, was standing right there. "All right, hey!" he said instead, letting his mouth take over and start rambling, start bull-shitting. His brain – his brain he needed to figure out what the hell had happened. Loki was here, but the wrong Loki; killing him might avenge Manhattan but it wouldn't fix the universe – this Loki was nothing more than a distraction. "All right, good job, guys. Let's just not come in tomorrow..." The bifrost schematics flashed through his head: he'd need it, or something like it, in order to have a real chance at tracking down Loki. "...Let's just take a day..."

Tomorrow he'd be busy. He had worlds to repair and a friend to avenge.

End Notes

Many thanks to my content betas, Cyphomandra and V, for helping improve this so much. Also, thank you to Acadecian for proof-reading this. My hat goes off to all of you. Any mistakes that remain are, of course, entirely my own fault.

Constructive criticism is welcomed. In particular, if you notice any formatting errors, please, please let me know, because trying to get it all to save properly (especially on this chapter) took a ridiculous amount of time, and I'm suspicious that it'll still be messed up.

I will be uploading the sequel stories soon; I just need to let my irritation at the formatting difficulties ebb first.

...

Notes on comics' canon:

For those who aren't familiar with the comics, Steve is from a variation on the 616 universe, where he was assassinated at the end of the Civil War event arc. Only apparently the bullets were 'time bullets' and... yeah, it got sort of wonky after that, hence why I say this particular Steve was from a variation on that.

'Clear azure eyes' is a reference to a certain comics panel (I would link, but FFN won't let me) where Tony does, indeed, go on about Steve's 'clear azure eyes'.

'Bob' is Robert Reynolds, aka the Sentry, one of (if not the most) powerful superheroes in the Marvel Universe – when he's capable of it. Reed Richards is Mr. Fantastic of the Fantastic Four, a super-genius at-or-above Tony's level. He does a lot of inter-dimensional stuff. After the end of Civil War, he decided to go see how it played out in other realities – and yes, Steve and female!Tony getting married really did prevent Civil War in that reality (again, I'd link if I could). Oh, comics.

...

Notes on Norse mythology:

I'm not a scholar of Norse mythology; most of my information about the texts discussed below comes from Wikipedia, so there may have been mistakes other than the purposeful ones (of which there were several).

Section 1 is titled after Gylfaginning (the Tricking of Gylfi), which is the first book of the Prose Edda after the prologue. It describes the basic layout I got as far as the journey into (and out of) Hel goes – along with a great deal of other stuff, too, of course; it's twenty thousand words and this was just one part. I picked it as a title for three reasons: 1) It's where this stuff is described and as far as I could determine the individual chapters don't have titles, 2) It is the first book (of three!) and there was other setup in it that I referenced, and 3) Gylfi is supposed to be a framing device. The section that I drew from describes Hel, her hall, Modgud, and the Gjallerbru.

Brynhild is taken from Helreið Brynhildar (Brynhild's Hel-Ride), which is found in the Poetic Edda.

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Section 2 is titled after Thrymskvitha (the Lay of Thrym), aka The One Where Thor and Loki Cross-dress. The translation I referenced while writing this is credited to Henry Adams Bellows (my profile page has a link). As well as the descriptions of oxen, I quoted some of the dialogue:

Thrym: "Bestir ye, giants, put straw on the benches! Now Freyja [I] bring, to be my bride, the daughter of Njorth, out of Noatun!"

Thrym: "Many my gems, and many my jewels! Freyja alone did I lack, methinks."

Thrym: "Why so fearful, the eyes of Freyja? Fire, methinks, from her eyes burns forth."

Loki: "No sleep has Freyja for eight nights found, so hot was her longing for Jotunheim."

...

Section 3 is titled Ragnarøkkr for reasons that are hopefully obvious.

The three roosters crowing is said in the Völuspá (the Prophecy of the Völva) to herald Ragnarok (or rather, one of its beginning events – liberties taken, etc): an unnamed 'sooty-red cock' crows in Helheim; Fjalar (a crimson rooster) crows in the forest of Gálgviðr ('gallows-wood') in Jotunheim while a jotun herdsman plays a harp; and Gullinkambi (a golden rooster) crows in Valhalla.

Many of the other descriptors of Ragnarok that occur in Section 3 are also taken from the Völuspá; the rest are from Gylfaginning. In the myths of our world Loki and Heimdall do end up slaying each other (Frigga's version); Tony's version of the myths is some of that AU!Norse mythology mentioned in the tags. There are a few other things that are AU as well, but that's the most blatant one (aside, of course, from Loki being Thor's adopted brother).