AN: can't stop, won't stop - another sastiel fanfiction. Enjoy!

Panicked and panting, Castiel ran through the many corridors of the dilapidated office building, his wild eyes scanning every would-be boardroom and break room. He was given to understand that this type of building was too expensive in the current economic climate for any company to afford to rent. This, however, meant that it was a prime target for supernatural beings to infest, or to squat in; the number of supposedly abandoned structures many city-dwelling people passed in their everyday travels that were actually havens for evil beings was significant, to say the least.

But Castiel wasn't thinking about any of those people right now. He could only think of Sam.

He was running in the direction Dean had told him to take – you go that way, I'll take the left side, and hurry for fuck's sake – not that he needed to be told to hurry. He was beginning to tire: the building was many, many floors high, and Sam could be in any room of any floor. Being unable to use the abilities he usually possessed to scan the building and transport himself to Sam's location was like torture.

He couldn't think coherently; he understood, now, why when Sam felt tired, or worried, he would say that he could not 'think straight'. His forehead would crinkle, he would frown, and rub his temples. His lips would purse, and his voice would grow low and soft. Cas always knew what to do in that situation: he would envelop Sam, as best he could, in an embrace; suggest he come to bed. Then they would lay together, convalescing, and listening to one another's heart beats. Sam found it deeply relaxing and, when he was relaxed, Cas was too.

But there was no one to do the same for him, right now: Cas was alone, with no one to comfort him, or tell him everything was going to be okay. Because there was a good chance it wouldn't be okay: Sam had been taken by a witch, who needed a human who had been a vessel for an archangel, for a rare spell that would provide her with power the likes of which had never been achieved by any other witch. This was purely because no other witch had ever seen able to obtain a living, breathing human who had been an archangel's vessel who wasn't either dead, or unable to function.

Unfortunately, he and the Winchesters hadn't figured out that it was an archangel's vessel (rather than simply an angel's vessel) she needed, before Sam – being uniquely the only used vessel currently on Earth – had been taken.

That was Sam, alright. Unique. Completely unique, and terrifyingly human. Vulnerable, somewhere in this office building.

Though almost completely fatigued, Cas forced himself to run still faster, as he entered the staircase up to the 21st floor.

Sam scowled up at the witch, dealing with something or other on her black alter, whose presence was incongruous with the shiny glass and chrome of the empty office space. Pretty smart idea to use this place: hardly anyone came by, and it was hard to get to where they were – the 37th floor, by his estimate from looking out of the window and comparing their height to that of the floors on the next building – at least, it was hard to get there quickly.

Maybe the 37th. Maybe the 38th? . . . 37th? 46th?

He shook himself, trying not to completely check out. She'd really done a number on him.

Fidgeting where he knelt on the floor, he tried the ropes that bound his hands in front of him; he caught the witch's eyes for a moment, causing her to smirk, and him to spend what little energy he had on scowling harder still.
"So – you're gonna kill me, and become a really powerful witch," He said, but was slightly put out when his voice came out as nothing more than a croak. He persevered, however. "Then what, win American Idol?"
"Actually, I was thinking of offering my services to a demon you may know. Honestly, honey – the level of power I'm gonna have, Abaddon will be begging to keep me around," She chuckled.

Sam gulped at the mention of Abaddon's name: he'd never really told anyone what had happened when she'd kidnapped him, intending to trade his life for his grandfather's. Needless to say, the demon was ruthless. And terrifying, even to him. His vision blurred for a moment in remembrance – or was it because his brain was trying to get him to shut down? To lie down, and sleep, and-

Shaking himself again as if he could disperse the fog in his mind, he wished repeatedly that he could slip these ropes; the witch had cast a spell on him to weaken him, causing his movements to be sluggish and exhausting; his thoughts to be slower than usual, and his words a complete battle to produce.

"Besides – this spell doesn't require your death – just a bit of your blood, and your hair, the usual – but it does require a human sacrifice, so why not use you for that too?" She sounded unreasonably reasonable, talking about his murder. "And don't you think Abaddon will be happy when I kill one of the Winchesters?"

Sam's lethargic face became wrenched in anger, as she continued: "Your brother will follow soon – he's always reckless when it comes to his little Sammy getting hurt. Every witch knows that . . . And then there's your little angel – or should I say, has-been angel,"

Taking up a knife from the alter, she approached him then, staring down at him for a moment with a wicked smile. She knelt down next to him, pressing the knife to the side of his face in a gentle caress. He flinched, not having enough energy to mask the reaction. She smirked.

"Word is, he's become very, very human these days. Eating, sleeping – and fucking," She nicked his skin at that point, cutting his left temple and making him hiss quietly. His eyes were filled with hatred as she continued, her voice husky and almost seductive.
"Imagine how easy it'll be to kill him when he's got no Winchesters to protect him. No protective older brother – no slutty younger brother. It'll be like shooting fish in a barrel," She smiled again, her face twisting in glee as she imagined the anguish she would cause with her new-found power.

Sam huffed out a laugh, causing her to raise her eyebrows, withdrawing the knife from his face.
"You think Cas . . . Is just some defenceless kid, or something? Cas is a hunter. Just like us . . . And your spell won't work," He was struggling to speak, and his speech marred by stuttering, but he didn't care anymore. "N-none of the other f-former-vessels you kidnapped did the job, s-so . . . You kill them. What . . . What makes you think I'll be . . . Any different?" He asked, trying to sound more confident than he was.
"Because, Sammy, you were an archangel vessel. Not only that – you were Lucifer's vessel. Raphael, Michael, Gabriel . . . Their vessels are all long gone, thanks to your little trio of fuck-ups. But you're still around, ain't you?" She smiled again, and he felt as if he was about to vomit.

Despite this, he made the conscious effort to consider what she'd said: it did make sense. All signs pointed to the fact that she'd tried to use angel vessels before, and almost completed her spell, before failing at the last part. This had caused her to become more desperate, until finally, she'd kidnapped one of the hunters that had been hunting her.
"If you don't work then, well . . . I guess I'll just kill your brother and your fuck-buddy anyway. Abaddon will still be pretty grateful," She decided with a despicably nonchalant shrug.
"Sh-she'll kill you. She doesn't want help from humans . . . And you're stupid if you think she d-does," He warned her.
"Well, that might be true . . ." She raised her knife again, and it glinted in the greyish-white of the office's bar lights. "Let's find out, shall we?"

She grabbed a handful of his hair, tipping his head forward forcefully, and he felt some of his hair brutally cut away from his head. When she released him, he saw a handful of hairs of random lengths in her fist. Then, she raised the knife again, and slashed down his wrist. He yelped, squeezing his eyes shut, but unable to struggle away.

He was just so tired, and yet he knew that it would be foolish to sleep; she could do anything to him, and it didn't look like Dean or Cas could help him now. It didn't look like they were coming.

What if they never came? Not even when he died?

What if they'd given up, gone home – Dean no longer having to look after his stupid little brother, Cas no longer tethered to a weak, pathetic, good-for-nothing-

He sobbed quietly – oh, so quietly – at the thought, and because of the pain. It was so much worse than when his wrist had been slashed open before: the spell was having an adverse effect on his ability to deal with it stoically; he knew that if Cas and Dean were coming for him, they would probably be too late.

She paid no attention to him, as she gleefully soaked the hair in the blood, watching the red, thick liquid glint just as the knife had, as it drizzled onto the dark brown locks.
"Pretty on the outside and the inside," She whispered, a wide-eyed unhinged expression on her face, causing him to look up at her in disgust, even when completely overcome with pain, emotion, and the ever-more-present need to sleep.

She took her spoils to a bowl he'd seen her prepare earlier, and dropped them in. She faced him, as she began chanting in Latin: words he'd heard before, but that his mind was too bleary to properly translate or understand. He didn't know if it was the old spell, the new spell, or the blood loss, but the light in the room was growing greyer and dimmer, while the scratching of the rope on his red-raw wrists was becoming more and more painful; the throbbing of his gushing wound becoming more hot and visceral.

His half-lidded eyes were glued to the witch, as her voice reached a crescendo; she was clearly nearing the end of the spell: he noticed her pick up a can of gasoline and fish a lighter out from her pocket after setting the bowl down, and approach him. He could see the insanity in her eyes, red and insidious.

Unscrewing the can of gasoline, she set about pouring it on him: on his knees, his shoulders, his arms, and a little on his head. She discarded it when she was done.

Sam remembered working in an office, once, for two or three days. That had been down to angels: it was funny, how even the most normal things they'd done in their lives, were completely . . . Not-normal. They were always at the mercy of angels, ready to be manipulated at any time. Their entire bloodline had been forged – entire lives lived – just so that he and Dean could be born to be to be celestial playthings.

He wondered if Castiel had known that all along; had been on-side with his brothers and sisters, steadfastly believing that free will was never an option.

He wondered if he'd surprised even himself when he chose the Winchesters, human and vulnerable, over a cast-iron millennia-old plan. He wondered if he was surprised when they won.

But he hadn't completely escaped the role that destiny had chosen for him.
Here he was, in an office building again, because he'd had an angel intervene in his life. Here he was, about to die.

She flicked the lighter on. It was only then that he realised, in his delirious state, that she intended to burn him alive as her method of human sacrifice. He squeezed his eyes shut to the sound of faint hysterical laughter coming from one corner of his mind, forcing it to go away by concentrating on the pain of the slash in his skin. Instead of going blank, however, his mind chose to think more about what could have been . . . If he'd ended up working in an office building, maybe – maybe a place like this would be part of his normal life, with a white picket fence, and two kids, and a dog, but – but he wouldn't be with, wouldn't know –

Would it even be worth it, if he never got to see the things he got to see in this life? If he never got to do good, and sacrifice himself for the times he sinned . . . If he never got to meet Castiel?

He could hear his voice now, laughing in childish excitement at the most simple of sensations: a tickle-fight on the sofa, which turned into something much less innocent – was it only a dream? Could he actually hear Cas? . . . Had Castiel even stayed, or had he left him alone, all alone, in Hell, to burn alive –

"Step away from Sam," Growled a gravelly voice, drawing Sam's glazed-over eyes and waning attention. He dragged his eyes up to see Castiel, standing behind the witch, his angel blade pressed to her neck. Very much here, and very much just in time.
"Oh – it's your prince charming, Sammy. And they say chivalry's dead," She jibed, flicking the lighter on and off over and over again. A boast.
"Stop," Cas insisted, pressing himself a little closer to her back – a mistake, as it turned out.

She elbowed him in the gut, causing him to stagger back; already tired from the run up the stairs, and from his swift sprinting through every floor on the way up to the 37th, Cas looked like a gust of wind could fell him at this point. Sam knew he couldn't shut his eyes now: he had to see that Cas was okay. He needed Cas to be okay, and maybe if he watched – maybe if he stayed awake, and paid attention – maybe, then –

"Angel wants to knife fight?" She asked him, grinning maniacally. Pocketing the lighter for now, she snatched up her knife from the floor beside Sam, where she'd left it. She flicked it several times, taunting Castiel with her skill, and telling him: "If you want to get to him, you'll have to go through me,"
"Funny. I was going to say the same thing," Cas replied. Sam eyes fluttered shut for a moment as he smiled gently, despite himself: Cas had clearly learned from him and Dean, quipping and joking in the face of danger, simply because it was all he could do. And to bide time, of course. Time which Sam didn't have, he realised, as he made a conscious effort to look at the wound in his wrist, which was still bleeding sluggishly.

Cas lunged forward, pretending to go for her right side, but actually striking her left with a punch. She was ready, though, and managed to strike back, with a very shallow scrape to Cas' belly. He hissed, but wasn't head to give it yet.

Sam watched the fight with owlish eyes: he couldn't even make out much besides her grey shirt, and his red hoody – everything was blurred, and surreal, and he just hoped that Cas wouldn't get hurt because of him, please don't let Cas get hurt for me again –

When she went in for a killing blow in the midst of the fight, striking down from above in a stabbing motion, Cas grabbed her arm, twisted it round behind her, and stabbed her in the back. He felt the blade pierce her heart, and heard her choke, surprised that she'd been beaten.

"When you get to hell," He whispered in her ear, his voice ragged and threatening, "You tell them that you're there because you thought I would let you get away with harming Sam Winchester,"

He pulled his blade from her back, and discarded her body onto the floor carelessly. Frantically, he skidded to his knees beside Sam: he'd noticed before that Sam had seemed in some sort of delirium; fatigued, and unable to keep fully awake, in addition to his injuries.

Now, though, he was more fully conscious, and was biting his lip in an effort not to cry out from the pain in his arm, which was still bleeding. Cas took off his hoody, and wrapped it tightly around the wound to stem the bleeding – just like Sam had taught him. It could save your life one day, he'd said: but Cas had listened because one day, it could save Sam's life. And that was more important.

That day, clearly, was today.

Sam stank of gasoline, and drips of it ran through his hair and onto his face; his clothes were soaked with it, as well as with Sam's own blood. Cas noticed that she'd cut a chunk of Sam's hair away, leaving an uneven patch behind. He smoothed Sam's hair, over and over again, until it was unnoticeable; this soothed Sam, who was currently trying to talk:
"C-C-Cas-" He stuttered, shaking with the after-effects of the spell, as well as from the pain he was in.
"Shh – Sam – it's-" As he cut Sam's bonds with his angel blade, he was tried desperately to remember what Sam had said to him in these kinds of situations to make everything seem okay, but the words just wouldn't come. So he just had to improvise.

He leant forwards, wrapping his arms tightly around Sam and cupping his cheeks, looking at his pale face for any sign of serious injury or trauma. Finally, his eyes caught Sam's, which were tearful and wide; frightened, maybe.

So Cas did all he could: he pressed his lips to Sam's, and though he tasted like gasoline and tears, to Castiel, he tasted sweeter than ever simply because he was alive. Not bleeding out right now, not burned to death, but alive. He'd done it: he'd rescued Sam, without his angel powers. Sam responded eagerly: he'd clearly been afraid that he was going to die, too.

As they pulled away from the kiss, pressing their foreheads together, Sam whispered: "S-see? You're – you're still useful," Cas huffed out a tiny laugh that was mainly based on his relief at getting there in time to save the day. He eyed the wound on Sam's wrist for signs that it was worsening, but saw nothing. So, he allowed himself to relax for a moment more.
"I surprised even myself," He admitted quietly, squeezing his eyes shut, and threading his fingers into Sam's hair. The tactile sensation helped to convince him that Sam was okay, there, safe, alive, despite the fact that Cas' rescue hadn't exactly been the same divine intervention that it usually was.

He decided that it was about time for them to leave this place, and get Sam to Dean, who could provide him with proper medical attention and determine whether or not the curse the witch had put on Sam to make him weak and fatigued would wear off – though, by the looks of Sam now, her death would suffice to reverse it. He took Sam under the arms, and gently helped him up. Sam hissed, his knees protesting after having been made to kneel for so long on the hard ground.

As they began to make their way slowly out of the room, Cas took out his phone with one hand, while supporting a shaky Sam with the other. He was about to dial Dean's number, when Sam's soft voice interrupted him:
"I'm sorry," Sam muttered. "For – for letting myself be-"
"It is not your place to apologise," Cas interrupted him gently. "I can only say that I, too, am sorry I didn't get to you sooner,"

He went to dial the phone again, but Sam stopped him again:
"Thank you," Sam told him, looking into his eyes with a heartfelt expression of love and gratitude. "Thank you, Cas,"

Castiel, though taken aback by the pure emotion on display right in front of him – emotion reserved for him – managed to reply: "You're always welcome, Sam," He kissed the younger Winchester on the cheek, and murmured: "Always,"