The air whistled, kunai zipping by Kakashi's face. It missed by a hair's width as he twisted to the side. He shot his arm out, snatching it from midair.

Just in time.

Obito descended on him with a snarl, eyes wild, long metal rods extending from his sleeves. The air rang with the clash of metal. And for a split second, they were at an impasse—weapons locked, staring each other down, both determined to win.

Kakashi studied Obito's face. Scarred, contorted into an ugly snarl, nearly twenty years older than when Kakashi had last seen him, thinking he'd said his final goodbye—yet he looked so familiar all the same. Kakashi couldn't shake away the similarities that he saw at every turn, in the shape of Obito's eyes, the curve of his jaw. His mind seemed hell-bent on transposing the illusion of a younger Obito over the face of his former teammate and current madman, and he was finding himself hesitating and freezing up at all the wrong moments.

…No.

He couldn't think like this.

Obito was his enemy.

The man had killed Minato and Kushina. Set loose the Kyūbi no Kitsune on Konoha. Murdered thousands. Declared war on the entire shinobi world.

Obito had said it himself; Konoha, Kakashi, his dream to become Hokage—those were all dead to him. His actions made himself crystal clear, no matter how desperately Kakashi wanted to be proved wrong. The old Obito was gone. Kakashi couldn't afford to let his emotions cloud his judgement, not now, not with the fate of the entire world on the line.

Kakashi grimaced, his eyes darkening. He had been in ANBU; he knew how to push emotions away, shove them into a box and throw away the key. He needed to do that now. Obito was too far gone, and nothing Kakashi had said—or could say—would get through to him.

Time unfroze, and Kakashi and Obito sprang apart.

He could do this.

Obito was not his friend.

Not his friend.

He took a deep breath. In a single, fluid movement, Kakashi yanked his hitai-ate up, closing his right eye and opening his left, feeling the familiar rush of adrenaline as everything became clearer, brighter, and pulsing with chakra.

Obito sneered at him. "Finally found your resolve?" he asked, his voice harsh and mocking. He wiped the blood off the cut on his cheek and looked down his nose at Kakashi. "Took you long enough."

"Maybe," Kakashi said. Without taking his eye off Obito, he let his hands fly into the almost comfortingly familiar hand signs. Ox, Rabbit, Monkey. "But this is where your schemes end," he said, low and steady. An undercurrent of steel ran through his words. "Here. Now."

The stark silence of the Kamui dimension was shattered by the shrill peal of concentrated lightning, and the dim surroundings erupted into blue light.

Obito barked out a short laugh. "Is that so?" With a twisted grin, he brought his hands together, forming seals of his own.

"I swear," Kakashi said. "By Rin's memory."

Obito snarled. "You dare—then show me what you've got!"

Kakashi charged forwards, and Obito met him in the center of the wide, gray platform. The air exploded into lightning and flames.

They exchanged punches and kicks with equal ferocity. Every then and again, ninjutsu would come into play, filling the dark landscape with earth, flame, and lightning. Obito's flames were blocked by Kakashi's mud walls, but all of Kakashi's jutsu attacks were easily countered by Obito's Rinnegan. To Kakashi's surprise, Obito was holding his own—no, more than that. Obito was matching him, blow for blow.

Obito, Kakashi realized, had been holding back as well.

Of course. Time passed; people grew. Just as Kakashi was no longer just "the traitor's son", Obito was no longer just "the idiot Uchiha".

The fight dragged on. The hints of heaviness in Kakashi's muscles that had come from fighting non-stop all day began to morph into full-blown exhaustion. His chakra reserves, which could normally keep him going past his collapsing point, were running low, and draining faster with every wall of earth and lightning clone that he was forced to use.

It was simple fact that Kakashi would not be able to keep this up for much longer. Obito had more chakra and more energy, and would soon have the upper hand.

With dawning dread, Kakashi realized that their fight would end in one of two ways: with Kakashi dead in a few more minutes of fighting, or—at best—with a stalemate, if he managed to find another opening to use Chidori. But using Chidori always left Kakashi open, meaning that Obito would no doubt deal him an equally devastating blow.

Either way, Kakashi wasn't leaving this dimension alive.

Wait.

No.

There—there was a third option.

Kakashi… could leave this place, alive, right now. It—it was the coward's way out, retreating, escaping, but… Kakashi was dead if he stayed here a second longer, and—to the left!—he was already starting to slow. Obito had a mad grin on his face—he was clearly aware that the fight would soon be his.

I'm sorry, Naruto, Sakura, everyone. I… I tried my best. I swear, I'll make up for this.

Kakashi leapt back.

"Running, Kakashi? I'm afraid there's nowhere to go—"

"Kamui!"

Kakashi's vision blurred as reality twisted in front of him. He saw Obito's enraged expression as the man leapt at him, but Kakashi forced himself to concentrate, pouring as much chakra as he could—every last drop—into the Kamui, fully aware that if he wasn't fast enough, he was leaving himself open for an iron rod through the heart.

What he wasn't aware was that if he wasn't precise enough, he wouldn't be the only one to be caught in the Kamui.

"You—" Obito gritted his teeth, trying to rush forwards, but his very torso was warping away in front of him. "What are you doing?!"

No, no, he didn't want to bring Obito with him—dammit! Kakashi cursed his poor handle on his left eye. He should have trained more, should have learnt to unlock the Mangekyō sooner, should have made that last mud wall just a little smaller—

"Kamui!" Obito glared at Kakashi, livid, his Sharingan spinning.

—And suddenly the world reeled, the grey landscape of the Kamui dimension seeming to fold and collapse in on itself as the regular distortionary effects of Kamui increased a hundredfold. All Kakashi could see was the look of confusion on Obito's face before suddenly he felt like his organs were being ripped out of him, every inch of his being on fire and this wasn't Kamui—

Reality collapsed, with Kakashi at the center, and he found himself left in a place that he understood instinctively was neither here nor there, an indescribable place that wasn't a place, with no direction or dimension or duration—

He was back, light, there was light, and sensation, and life, and despite his body feeling a little strange and… small, Kakashi exhaled in relief that whatever that had been, it had worked out after all, because this was, surely, without a doubt, Konoha.

Wait.

Konoha?

"Kakashi!" came an oh-so-familiar voice, from an oh-so-familiar face of blond hair and blue eyes.

Kakashi blinked, brain registering just who was there in front of him.

His jaw dropped.

Minato picked up the tantō he had just knocked to the ground and handed it back to his scowling opponent. "That was great, Kakashi," he said with a smile. "I can tell how much you've been practicing with this."

"One more round, Sensei—this time I'll win."

Minato laughed, shaking his head. "That's what you said the last three times. You've made amazing progress already today, it's fine if you take a little break, you know." He ruffled Kakashi's hair.

Kakashi glowered, jaw set. "Last round." He got to his feet, settling into a ready stance. He raised his tantō in front of him.

"Last round?" Minato quirked an eyebrow. "Promise?"

Kakashi stared, his frown visible even under the mask. "…Fine," he said grudgingly.

"Then three, two, one—begin!"

A smile on his face, Minato let himself fall into the familiar and comforting movements of blows, kicks, blocks, and dodges, the movements flowing like the steps of an intricate dance as they spun and ducked their way across the field.

Kakashi was good—jōnin level already. Unfortunately, Minato thought with a smile as he clipped Kakashi on the arm, Minato was very good.

Still, Kakashi was always Minato's favourite to spar with, if only because the thirteen-year-old was the only one of his teammates who presented a serious challenge. With Kakashi, Minato could even use a few Hiraishins here and there.

Not that Obito and Rin weren't adorable little chūnin as well—Kakashi might be leagues ahead in taijutsu, ninjutsu, and even genjutsu, but his social skills were abysmal, and his worldview a little… concerning, to say the least.

That was where his teammates balanced him out; Obito's sheer enthusiasm and determination in everything he did brought life to his team, even if Kakashi didn't know it, and Rin's sweet, gentle personality was able to diffuse even the bitterest of fights between her two stubborn teammates.

Minato grinned from a treetop in the distance as Kakashi hurled a barrage of shuriken at a clone, only to realize too late that it was a copy. With a little twirl of one of his three-pronged kunai, Minato flung it towards Kakashi. He knew Kakashi would dodge it easily, but Minato would then be able to teleport behind him, in prime position to catch Kakashi unawares and attack—a classic move of his.

He frowned, watching as Kakashi seemed to stumble over nothing. He hadn't noticed the kunai yet. He was just… standing there, for some odd reason, glancing almost uncertainly at his hands and surroundings.

Minato's eyes widened. He leapt out of the tree. Kakashi hadn't noticed the kunai yet.

"Kakashi!"

Kakashi's head snapped towards him, and Minato would have taken a step back in surprise at the look of sheer shock in those wide eyes if there hadn't been a kunai inches from his face.

And then Minato remembered it was one of his tri-pronged kunai. As in, Minato could teleport to its location.

He was an idiot.

He was just about to activate the kunai's Hiraishin seal when Kakashi finally seemed to become aware of its existence. With startling speed, he caught the center prong of the kunai between his thumb and forefinger

The tip was less than an inch away from his face.

Minato sagged, exhaling in relief. And then straightened, remembering that Kakashi had very nearly taken a kunai to the face.

"Kakashi, what were you thinking?!"

Minato.

Minato was standing there, young and whole and alive.

For a moment, all Kakashi could do was stare, transfixed to the spot, his brain scrambling to make sense of not just his sensei standing there, but also of thousands of other tiny little details.

Like how despite having his left eye open, ready for combat, his vision looked… normal. He couldn't see the flow of chakra, didn't have the sharper, brighter vision of the Sharingan, didn't even feel the drain of chakra that came from opening his left eye. If he didn't know better, Kakashi would have sworn he was seeing through a normal eye.

And despite standing upright, Kakashi was suddenly a whole lot closer to the ground than he remembered being. His body felt… smaller, as strange as it sounded. As if he were back in the body of a child.

Yet despite that—despite the odd sensation of suddenly being… less, than before, Kakashi felt fantastic. His bones and muscles still ached, but it was the routine ache that came with standard, everyday training, not the burning exhaustion that he had been under moments ago. His chakra coils also felt oddly… lesser, but his reserves were now back up to stable levels.

And this place—it was, without a doubt in the world, Konoha's third training ground. Kakashi recognized the three time-worn posts, the little ring of trees behind it, the grassy expanse spotted with patches of soil, the winding river in the distance. How had he ended up here, of all places? And—hadn't it been nighttime?

The whizz of a kunai jolted him back to attention. With a start, Kakashi finally registered the pointed object flying towards him.

Right—he still had an unfinished fight with Obito. Shooting his arm out, he grabbed hold of the kunai just in time, the blade a finger's breadth from his face.

Or should he say blades, because, Kakashi realized as he stared at the kunai in his hand, this wasn't just a standard kunai—it was one of Sensei's old tri-pronged Hiraishin kunais.

"Kakashi, what were you thinking?!"

Wait. Who had thrown the kunai, then? Kakashi narrowed his eyes. Minato was dead. He was fighting Obito right now.

…Obito, an Uchiha.

This was a genjutsu.

Kakashi slammed his hands together into the Tiger seal.

"Kai!"

The Minato impostor paused, seemingly taken aback at Kakashi's angry outburst of chakra.

"Kakashi? Look, I understand you want to show off a little, but catching the kunai like that was an incredibly dangerous move! Save those moves strictly for when you're on the battlefield, alright?"

Kakashi wasn't listening. Or tried not to, at least—tried to ignore that concerned voice, so achingly warm and familiar that Kakashi knew if he let it, his mind would drown him in the bittersweet memories.

Obito, Obito had to be the cause of this—probably yet another unholy jutsu ability that came with having both the Sharingan and the Rinnegan. Kakashi flung out his chakra, trying to sense Obito's location—he had to be somewhere nearby.

Whatever Obito had done—somehow recreating this memory from Kakashi's childhood—he wasn't going to get away with it. With this newfound energy, Kakashi was going to rip him apart. Using a phantom of Minato against him? That was low, too low.

There!

Approximately a hundred metres to the left, behind the little patch of trees—Obito's chakra signature.

It felt wildly different, much more like the chakra signature of a thirteen-year-old Obito, but Kakashi couldn't afford to focus on those odd little discrepancies right now. Just like how both his eyes were for some reason perfectly fine, he was just going to have to go along with it.

Right now, dealing with Uchiha Obito was his immediate priority.

He gathered a burst of chakra in his feet and flickered to Obito's signature—

Only to blink and find himself staring at Rin. Rin with her wide brown eyes and brow furrowed in confusion, just like that day when Kakashi had shoved a Chidori through her heart, that day which Kakashi's traitorous mind insisted on reminding him of even twenty years later, in sweat-soaked nightmares—

Kakashi's head snapped to the figure clad in orange and navy across from her.

"Obito," he hissed.

A split second later found two kunai clenched tightly in Kakashi's hands. He charged.

Kakashi would end this, now. Just as he had promised.

But then—instead of fighting him, Obito leapt to the side, hands raised, palms out.

What the hell was he playing at?

Obito's jaw was clenched, eyes narrowed in an expression that Kakashi couldn't quite place—anger? Loathing? No, it was more piercing than that—his eyes were sharp, guarded, almost calculating.

"Kakashi, stop—" Obito gritted his teeth and blocked another punch. "Listen to me—" A kick, followed by a swipe of Kakashi's kunai.

"No," Kakashi said, furious. "What did you do? What is this?" He punctuated the word with a hard punch that Obito only barely deflected in time. For some reason, Obito wasn't using Kamui. His eyes were a solid brown—both the Sharingan and the Rinnegan were gone.

"Kakashi, what are you doing?!" Rin sounded horrified.

No.

No, it wasn't Rin, it was an illusion, a disgustingly underhanded trick by Obito to try and play with his emotions. A distant part of his brain registered that "Minato" was now here as well, talking to "Rin" in a quiet voice.

"Genjutsu? Infinite Tsukuyomi? Another abomination cooked up by you and Madara?" Kakashi pressed forwards, fists and kunai flying, cursing his smaller body that wouldn't let him hit as hard or reach as far as he was used to.

"And—" Kakashi's eyes tightened, remembering Rin and Minato off to the side, and he swept his leg out in a kick. "Them. Here. How could you?"

He drew his arm back for a punch, only for a hand to catch his wrist.

Minato.

Of course. This entire illusion was under Obito's control. Despite Minato and Rin's appearances, they were the enemy as well. Obito, the bastard, took the chance to jump away.

"That's enough, Kakashi." Minato's eyes were hard as steel, his mouth set into a thin line. "What's going on?"

What's going on?

Kakashi curled his lip. "You tell me, Sensei." He flicked his eyes to the "boy" across from him. "Obito, if this is Infinite Tsukuyomi, it looks like you've made a mistake. This is a hell, not a heaven."

Minato's grip tightened on Kakashi's wrist. "Alright. What are you talking about? Kakashi, this isn't like you—"

He startled in surprise as the Kakashi he was restraining melted away into water, the real Kakashi having substituted himself with a clone that had been hidden in the trees.

Obito tensed, glancing around him. He opened his mouth to speak—then cursed as a hail of clay needles raced towards him from out of the treetops.

Rin cried out in shock, and Minato's sharp voice cut through the air. "Kakashi! That is going too far! We're training, not fighting!"

For a split second, Kakashi exhaled in grim satisfaction as the spikes slammed into Obito's chest and abdomen—that jutsu had taken way more out of him than it should have—only for Obito to disappear a millisecond later, a log in his place.

His clipped voice rang out from below Kakashi. "If you want answers so badly, stop trying to murder me and let me speak!"

Kakashi twisted around with a scowl. Nevertheless, he forced himself to lower his kunai.

Obito glared up at Kakashi. "…I have no idea what's going on."

Kakashi clenched his kunai. "You're lying—"

"I swear on my life that this is not one of my genjutsu, Infinite Tsukuyomi or otherwise." Obito shot a glance at Minato, who was looking at them with suspicion clear in his eyes. He pursed his lips, and a moment later, was standing next to Kakashi on the tree branch.

Kakashi flinched, whipping his kunai up defensively.

Obito's eyes flashed in irritation. He lowered his voice to a soft hiss. "Use your head, Bakashi, instead of charging blindly like an idiot. Kamui is a space-time ninjutsu. All signs so far point to one clear conclusion."

Kakashi froze. His left hand, which had been lightly pressed against the tree, clamped down with a grip that caused the bark to splinter with a crack.

Impossible.

…But then again, what did he know? Kakashi had seen his entire village resurrected by a single man, watched as Uchiha Madara himself returned from beyond the grave. He himself had died, had even had a conversation with his dead father, but then was returned to life.

If life and death were concepts so easily played around with, well, who was he to say that time wasn't the same?

Then… that really had been Minato back there.

And Rin, too… gods.

What had Kakashi done? What the hell was he going to do?

How would he explain his actions to Sensei and Rin?

How was going to get back?

Obito exhaled sharply, running a hand through his hair. "Finally," he bit out, a sarcastic smile on his face. "I was beginning to question if you had a brain."

Kakashi bristled. It had only been reasonable for him to assume it was a genjutsu—Infinite Tsukuyomi was Obito's entire objective, after all. He opened his mouth to retort.

And then the tree branch creaked as a third person made their way up to stand between Kakashi and Obito.

"Boys. What is going on between you two?"

Suddenly, it was as though Obito had morphed into a completely different person. Kakashi stared, the transformation taking place in the literal blink of an eye. Obito's spine went from rigid to slouched, his hands from clenched to relaxed, his face from a mocking sneer to a sheepish smile.

"Er, sorry, Sensei," he said. "I might have put a little genjutsu on Kakashi earlier."

Minato frowned, suspicious. "What? Where did you learn a genjutsu?"

Obito looked off to the side, fidgeting. "She made me promise not to tell," he muttered.

"She?"

Obito froze, back going ramrod-straight. "Shit!" he squeaked.

Yes, Kakashi realized in amazement, he had squeaked. It was almost comical; the instigator of the Fourth Shinobi War and wielder of the Rinnegan, squeaking.

Kakashi would have cracked a smile, but he was still too busy reeling from the idea of time travel.

"Language! Who was it, and what did she teach you?" Minato crossed his arms, and raised an eyebrow. "You know, Obito, I have ways of making you talk."

Obito's eyes widened. "Okay, okay! It was…" He bit his lip. "…Kurenai. The hell-viewing technique," he grumbled.

Minato creased his brow. "Obito! That's an extremely cruel prank to play on a fellow teammate. Apologize to Kakashi."

With a huff, Obito turned to face Kakashi. "S'rry," he mumbled.

Inwardly, Kakashi marvelled at Obito's act. But that was right; this was the man (or was it boy, now?) who had played Tobi the village idiot for an entire year, fooling even the likes of the Akatsuki. But to be able to switch personas so easily, and lie so convincingly—it was unnerving. Obito may have just managed to assuage the suspicions of even Namikaze Minato, the Yellow Flash.

Kakashi himself, who knew Obito was putting on a show, was still finding himself hard-pressed to remember that the young preteen Obito in front of him was in reality an S-rank criminal ninja. It was so easy to just let himself be lulled by Obito's earnest-sounding words, trust his sincere-looking eyes—

"Hatake Kakashi! What you did was not acceptable, either. Especially that jutsu—those clay spikes could have killed Obito!"

Kakashi started, not really ready to be addressed by Namikaze Minato, who by all laws of nature should not be here addressing him at all. He wracked his brain, trying to remember how his younger self would have responded. Stubbornness? Anger? Self-righteousness? …Too in shock to think properly, he decided to just go with what he hoped would placate Minato the most for now.

He bowed his head a little, hoping he looked appropriately contrite. "Sorry, Obito. Sensei. I let my anger get the best of me." He retrieved Minato's kunai from his pouch and offered it back to him. "Apologies, about earlier. I didn't mean to alarm you. I won't do it again."

Minato stared at Kakashi like he'd grown a second head. Kakashi wondered if he should have channeled his inner Sasuke a little more.

"Er, that's quite mature of you, Kakashi." Minato slowly took the kunai back. He frowned. "You know you can always come talk to me if there's anything bothering you, right?" He glanced at Obito. "That goes for you as well, Obito."

Kakashi and Obito both nodded. There was a beat of silence.

"Well, then," said Minato, clapping his hands together. "How about we go back down instead of talking up here in a tree?" He chuckled. "I think this poor branch is just about to collapse under the three of us."

Obito gaped, offended. "Hey! Are you calling me fat?!"

"W-what? No, Obito, of course not!"

With a huff, Obito jumped down, grumbling something unintelligible under his breath.

Minato shot Kakashi an exasperated glance, who made sure to roll his eyes accordingly.

Grudgingly, he realized how excellent an actor Obito was. Kakashi remembered how ridiculously incompetent he himself had been when Naruto had smashed Obito's mask to pieces. He had frozen up like an idiot at the mere sight of a familiar face. He couldn't do that now.

They jumped down to join Rin and Obito, and Kakashi gave them a critical stare. Rin was fussing over Obito like a mother hen, and Obito was the very image of a cheery thirteen-year-old boy. Kakashi was likely the only one who saw the slight crease of Obito's eyes, the way he grinned just a little too brightly, how he was staring at Rin with an intensity that was just a little off the mark.

Seeing Rin again, he realized slightly guiltily, had probably hit Obito just as hard as it had hit Kakashi, if not more so. And maybe Kakashi's earlier accusations had been a bit unwarranted, with that in mind.

Right now, though, Kakashi needed to leave somewhere quiet to go gather his thoughts.

Time travel.

Kakashi never would have believed it, if the evidence wasn't like a giant Rasengan in his face.

There were so many questions on the theoretical level. How had it happened? How would he get back? Was this the same timeline? Would the future as Kakashi knew it cease to exist? Or was this not time travel at all, but an alternate universe, somehow branching off his original one? Was it even possible to head back?

And then there were the tricky little questions and implications. Would Kakashi have to work with Obito to find a way back? Would he be able to work with Obito? Did Kakashi have a duty to inform Minato of future events? The Hokage? Should he try to change the outcome of events he knew would end in disaster, like the Kannabi Bridge mission? …And that was coming up soon, too, wasn't it? Everyone's faces looked exactly as they did in Kakashi's nightmares, so it couldn't be more than a month away.

Kakashi needed to think.

"Sensei. Is it alright if I leave early? I'm not feeling well."

"Oh! Of course, Kakashi." Minato gave Kakashi a once-over. "It's not a cold, is it?" he asked, knitting his eyebrows together and pursing his lips in that way he always did when his team so much as got a splinter or let out a sneeze.

Kakashi struggled to stop a fond smile from creeping out onto his face. Not for the first time in his life, he thanked the gods for his mask. He gave Minato a short shake of the head, knowing his currently unstable acting skills would probably give his amusement away.

He… did do that, right? Just nodded at people asking him questions? Kakashi was pretty sure that at this age he had been a veritable ball of angst and snobby self-righteousness, so it shouldn't have been too out of the norm.

Just as he was about to turn around to head back, Rin reached out with her hand, a frown on her face. "Wait, Kakashi! Are you—"

She hesitated.

"Never mind. Just, get some rest, okay? Don't stay up training all night again."

Internally, Kakashi cringed, remembering once again just how consumed with training he had been at this age. Physically, it had done him a lot of good. Mentally… not nearly as much.

He gave a nod, glancing one last time at everyone's faces, trying to burn them into his memory.

Then, not really wanting to stay there a moment longer, he sent a burst of chakra to his feet and sped off. He told himself that he wasn't running away.

He almost believed it.

A/N: Hoo boy, get ready for an adventure! I've got this whole thing planned and outlined, should be a fun ride. I won't just be focusing on the Kannabi Bridge mission—rather, there's going to be a lot more to come, both before and after that point.

Tell me what you think of this first chapter! Any constructive criticism, your guesses for what'll happen next- I'd love to hear it all.

Edit: Some minor changes made as of Nov. 17, 2018, mostly just in dialogue to make it less OOC.