Disclaimer: I own not a thing.

Pairing: Kakashi x Sasuke

Re-Rejuvenated

By: yukuro

Stage One: Pre-teen

The infernal knocking on the front door still had not ceased.

Eighteen-year-old jounin Uchiha Sasuke had just returned from a tiresome mission and had been quite looking forward to a quiet, peaceful evening alone at home. Apparently, whoever was outside knocking had other ideas. He ignored it the first few times, but once the knocking began to sound in elaborate rhythmic patterns, Sasuke's patience began to grow thin. Slamming his chopsticks back down on the table, he stomped towards the front door. So much for his quiet evening.

"What do you want?" he snapped irritably, the second he pulled open the door with vigor. A frown settled on his face when cold air and empty space greeted his face. Just as he prepared to slam the door shut again, he felt a tug on his shirt.

"Yo, Sasuke!"

Sasuke blinked once. Then twice. A frown settled on his face.

In this amount of time, he had already checked that it was not genjutsu deceiving him, but his brain still could not process the information that his eyes were feeding him. This had to be a joke.

"Look, kid," he began in an exasperated sigh, slightly scowling as he did so, "I don't know who you are and how you know where I live, but please go home to your parents, and stop impersonating Kakashi. It's unflattering."

"You're cold as usual, Sasuke," the Kakashi-look-alike child said with cheer resonating in his voice. It was the kind of familiar cheerfulness that made Sasuke cringe in recognition. "But really, is that any way to treat your former teacher?"

"You're not Kakashi," Sasuke stated flatly. "You're a kid. You must be at least five times younger than him."

"Just because I have gray hair, doesn't mean I'm old," the child sulked. "I'm only thirty-two."

It took Sasuke a second to realize that he was actually having this conversation. Shaking his head, he firmly set a determined frown back on his face before stepping back into his house and pressing the door back towards the frame. "Good ni—"

"Were you eating dinner?"

Sasuke's eyebrow twitched. The child was no longer outside his door, but was now perched at the edge of his dining table, observing Sasuke's dinner. Fury invoked, Sasuke slammed the door and marched back to the table. "Who the hell are you? And what do you think you're doing in my house?"

"I told you," the child repeated slowly, as if speaking to someone younger than himself, "I'm Hatake Kakashi."

Sasuke was Not Amused. He was tired from his mission and now he was hallucinating. It had to be that or some random child thought it would be a fun prank to dress up this way and annoy the hell out of him. Pressing his lips into a thin, flat line, Sasuke said stiffly, "Prove it."

"Well," the child began musingly, taking a seat at the table, "when you were twelve, you co-conspired with Naruto and Sakura in putting a chalkboard eraser in the doorframe to fall on my head."

Anyone could have heard about that, Sasuke reassured himself, lips tilting downward. As realization hit him, he muttered under his breath, "That was Naruto by himself."

"When you were fifteen," the child continued carelessly, examining his nails, "I had to give you the sex talk because you decided you had to go check on the noises of two people coming from the bushes in the forest while we were training even though I specifically told you not to."

Sasuke's jaw nearly dropped openly as his cheeks flamed in embarrassment. He would kill Kakashi for blabbing to some kid about that. No one was supposed to know about that. Kakashi swore he wouldn't tell. Sasuke's brow twitched again.

At this point, the child was beginning to become quite amused. Cheerfully, he continued, "At sixteen you accidentally took my copy of Icha Icha Paradise instead of your record book. After reading just one page, you got so embarrassed that you took your kunai and—"

"T-That's enough!" Sasuke sputtered as he jumped to his feet in a rage, face thoroughly flushed. He glowered at the child's only visible eye, cheeks still blazing. "I don't know how you know that stuff, but…!"

"Still won't believe me?" the child sighed in disappointment. Reaching over, he plucked a mushroom off Sasuke's dish and popped it into his mouth after pulling his mask down a bit. Grinning, or as much as Sasuke could tell with that mask back in place, the child fished a folded sheet of paper out of his pocket and offered it to Sasuke. "It's a note from Godaime."

Still dubious, Sasuke snatched the paper with a frown while the child continued to help himself to Sasuke's dinner. With clear irritation on his face, Sasuke scanned the note rapidly.

It was ridiculous. Completely and utterly ridiculous.

"How did this happen?" he demanded, sitting back down again at the table. He fixed his gaze carefully on the child—no, Kakashi, or so he and the note claimed. "This is impossible! And why didn't you show me the note first, instead of spilling all of my embarrassing moments?"

Kakashi shrugged in amusement. He beamed up at his former student, who was now at least six years older than him bodily wise. "It was fun to remember your cute embarrassed face at those times."

"Hurry up and explain yourself!" Sasuke demanded, feeling his cheeks warm up again.

It had all started three days ago, according to child-Kakashi. He had just returned from a mission with a light graze on his arm. Apparently, the scratch was not a light graze after all.

"It was infected with poison," Tsunade had declared frankly, folding her arms. "Luckily, wasn't lethal and we managed to treat it. Why didn't you get it taken care of sooner?"

"My teammates had it worse than me," the then adult-Kakashi had explained sheepishly while rubbing the back of his head. "Plus I had to turn in the report."

"Reports can wait when you're injured," Tsunade snapped, feeling a headache coming on. She felt as if she were speaking to a novice genin, not Kakashi, one of the best of her best. Sighing, she continued with the more important news. "There's something you should know about the poison though. Shizune, tell him."

"It's a fairly new poison developed by the Rock Country," Shizune explained, taking over as Tsunade retired to a chair to rub her temples. "It was made to cause cell decay in the body. It's known to spread over time, so it's actually quite a surprise you've been fine for so long."

"Anyway," she continued, "Tsunade-sama was able to create an antidote, but it hasn't been perfected yet. In other words, while the antidote is working, you'll be experiencing side effects."

"Exactly what kind of side effects?" Kakashi asked intently.

Shizune cringed slightly. "Well," she said rather timidly, "the antidote needs to rejuvenate your cells, so experimentally, your body will get younger. It'll recover over time, but for a little while, you'll revert to a child form with rapid re-growth until you return to your actual body age."

Kakashi remained silent for a moment before asking, "How long will it take?"

"A few weeks," Tsunade replied in exasperation from her desk, shuffling a stack of papers together. "In the meantime, find someone to stay with to look after you. I would recommend Sakura since she can use medical ninjutsu, but she'll be out on a mission for a while. So find someone yourself."

"So you decided to choose me?" Sasuke asked rather skeptically with a sigh. He closed his eyes in exasperation for a moment when Kakashi nodded cheerfully. Opening his eyes again, he demanded, "Why?"

"Gai first volunteered to take me in," Kakashi explained rather dully. "But he said he was also planning on exploiting me."

Sasuke raised an eyebrow. He had no idea what was meant by "exploiting," and he frankly did not want to find out. He supposed he had to cut Kakashi slack there. Although, that did not stop him from commenting with a smirk, "I don't know, Kakashi. He really seems to like you."

Kakashi shot him a look.

Shrugging, Sasuke then suggested, "Naruto?"

"Have you been to his house?"

All right, admittedly, he shouldn't have brought that one up either. Sasuke's brow twitched yet again. Yes, how he hated to admit it, but there really was no other way. Kakashi had looked after him since he was an ignorant child. He supposed he owed the man—err, child some sort of debt. Giving up, he grumbled in resignation, "Fine. You can stay. Just don't trash my house when I'm out on missions."

"Never," Kakashi promised with little enthusiasm, making Sasuke frown deeper in obvious distrust.

Examining the boy before him, Sasuke finally managed to ask out of curiosity, "How old are you supposed to be right now anyway?"

Stretching his arms out, Kakashi examined them for a moment before shrugging. Upon observing this scene, Sasuke twitched yet again. Why, oh, why did Kakashi look so damn adorable like that? It was wrong on so many levels. First of all, Sasuke was supposed to despise kids. Second of all, he was supposed to despise Kakashi. There was clearly something wrong with his current mental processing. Across the table, Kakashi looked thoughtful for a moment before answering, "Almost ten or so. At least, it feels that way."

"You've got to be kidding me," Sasuke groaned in irritation. This was bad. It was almost as if he were teaching a class of genin—a job that he had readily turned down and decided maybe for when he was older and more mentally prepared to deal with the incompetence. But then again, he did work with Naruto for six years already. "It's like babysitting."

"I'll grow fast," Kakashi replied carelessly, waving his hand as if it were a small matter not to be concerned with. "At least, that's what they told me."

Exasperated, Sasuke gave in with a groan and sat back down at the table. He glanced at the table and frowned visibly. Most of his dinner had conveniently disappeared. He glared pointedly at Kakashi.

"A child has to eat," Kakashi said innocently in a sickeningly sweet tone.

Sasuke grumbled and collected his dishes before depositing them in the sink. So much for dinner. Deciding that he would come back for the dishes later, he made his way towards the bathroom to prepare himself a shower. He could feel Kakashi's curious gaze following him as he went, but he completely ignored it. Just because he was staying here, did not necessarily mean Sasuke had to take care of him.

Just before Sasuke pulled the bathroom door shut behind him, Kakashi called out cheerfully from the kitchen, "Have a nice shower!"

The dark haired teen promptly pulled the door shut in a rather stiff motion. Once he had the water running, he closed his eyes and let his stress-tensed body relax as the room steadily filled with gentle steam. He cracked his eyes open slightly to gaze lazily at his hazy reflection in the mirror as it continued to fog up with steam before progressively peeling his clothes from his body and slipping into the steaming shower.

As water beat gently over the top of his head, Sasuke managed to let his worries slip away for a short while. He continued to drown his worries for a while before finally reaching over to turn the water off. His skin was beginning to wrinkle.

Stepping out of the shower, Sasuke grabbed a towel from the rack and wrapped it around his waist before taking another to dry his hair. Once he was properly dried, he pulled some more comfortable home-wear clothes and retrieved his towels from the ground. Just as he was about to make his way back to his bedroom, he remembered that Kakashi was still outside. He frowned slightly and took a step back. Slowly, he glanced over his shoulder at the bathtub. Even though he had decided he would not bother to look out for his shrunken teacher, his conscience nagged at him to do so. Muttering under his breath, he marched back to the bathtub and filled it with warm water and placed more clean towels on the rack.

When Sasuke stepped out of the bathroom, it was blissfully but oddly silent. He slowly made his way back to the kitchen, where, much to his surprise, the dishes as well as the table were cleaned. Kakashi still sat at the table, feet propped up on another chair while pleasantly reading whatever new copy of Icha Icha Paradise he had. Again, something nagged at Sasuke's conscience. Frown settling on his face again, he was reminded of why he despised children.

Leaning over Kakashi from behind, Sasuke easily fished the book out of the child's hands. When Kakashi turned to pout, however it was possible with the majority of his face covered, Sasuke snapped the book shut and folded his arms. Pointedly, he stated, "I don't think children should be reading this kind of book. Go take a bath. I've filled the tub for you. You can wear whatever old clothes I have from when I was younger."

Kakashi was smirking at him, Sasuke could feel it. He almost cringed at the smug aura the child was radiating, but his pride promptly gave his cowardice the finger and made him stand rigid. He did blink in surprise, however, when Kakashi stood up on the chair and pulled Sasuke down to his eye-level by tugging on the teen's shirt before pressing an innocent kiss on the side of Sasuke's face. Watching the dark haired teen's face flush, Kakashi commented rather cheerfully, "Are you sure you were always a younger brother, Sasuke-niichan?"

"Don't call me that, you perverted jounin," Sasuke scowled in embarrassment as Kakashi hopped off the chair and made his way towards the bathroom, cheerfully humming as he went. Bringing his hand up to his face, Sasuke gingerly fingered the tingling patch of skin where Kakashi had kissed. The cloth of the mask had been in the way, but still his cheek flamed as if actual lips had met it. Once the bathroom door clicked shut, Sasuke cursed Kakashi under his breath. He should have known he would come to regret his decision.

When Kakashi emerged from the bathroom about half an hour later, Sasuke was still up at the kitchen table, finishing up the details on his mission report. The dark haired teen looked up when he heard the soft sound of footsteps coming towards him. He frowned visibly at Kakashi's state.

The clothes Sasuke had lent him were quite clearly too large, as Kakashi made clear with the flapping of the loose sleeves. If Sasuke had not been so distracted, he may have been able to better appreciate the fact that Kakashi presently lacked a mask and headband to cover his face. His hair was still dripping drops of water, making Sasuke's frown deepen. But if Sasuke was or ever would be able to associate the word "cute" with Kakashi, now would have been the moment.

"Give me that towel," Sasuke mumbled with a mixture of embarrassment and irritation as he snatched the towel from the child's hands. Turning around in his chair, he draped the towel over Kakashi's head before rubbing vigorously in attempt to dry the hair beneath. It was suddenly at that moment that Sasuke realized something.

He only had one bedroom and only one bed.

Kakashi peeked up at him from beneath the flaps of the towel draped over his head. Amusement in his voice, he asked, "Something wrong?"

It was quite possibly the only time Sasuke ever regretted leaving his family's estate to live in a tiny apartment in the city. If he were still in the estate, at least he would not have to share a bedroom, and most likely a bed too, with Kakashi, even if he was just a child presently. His left eye twitched slightly.

"Don't worry," Kakashi stated loudly, pulling the towel off his head to grin up at Sasuke's disturbed expression. "I won't molest you in your sleep. Although, it would be interesting given the state of the current situation."

"Bedtime!" Sasuke declared abruptly, almost jumping to his feet. Face blazing with a mixture of annoyance and embarrassment, he ushered Kakashi into his bedroom and sat the child on the bed. Once Kakashi was seated, Sasuke took a step back and ran a hand through his dark hair in frustration. Suddenly, Sakura's idea of keeping an extra futon in his house seemed like the greatest idea in the world—which made him the greatest idiot in the world for not listening to her before.

"Does it bother you that much to share a bed with me?" Kakashi asked in amusement, swinging his legs from the side of the bed. Sasuke stiffened visibly, making Kakashi raise an eyebrow. "Aha. So I hit the mark?"

"O-Of course not," Sasuke scowled, reluctantly edging towards the bed. The moment his gaze met the smug expression that adorned Kakashi's face, Sasuke felt his pride swell. He quickly strode over to the bed, and as Kakashi moved to the far end, he lay down and pulled the sheet up to his chin. Frowning and shutting his eyes defiantly, he stated with a sniff, "I'm not afraid of you."

If he had his eyes opened, Sasuke may have noticed Kakashi directing a sign of victory at the wall. Poor Sasuke. It always was hard for him to realize when he had been manipulated.

Sasuke stiffened when he felt the sheets shift and a body crawl close to his back. A bit too close. He could feel Kakashi's even breathing on the back of his neck, and much to his annoyance, his face heated up again. "K…Kakashi…!"

"Hmm?" Kakashi asked in an oblivious tone when Sasuke turned around to glare at him. Seeing this as an opportunity, Kakashi grinned and gestured towards his upward-turned lips. "Ne, Sasuke-niichan. Won't you give me a goodnight kiss?"

Completely and utterly shocked, Sasuke could only continue to glare while his jaw dropped open and closed again uselessly. Finally managing to get his jaw functioning again, Sasuke scowled, "I-Idiot! Go to sleep!"

Kakashi watched in childish disappointment as Sasuke rolled over to face the opposite direction again. Folding his arms, he declared, "Fine then. I'll just help myself."

This comment made Sasuke's ear perk. What the hell was Kakashi talking about? He turned his face slightly to glance back in curiosity—a terrible mistake on his part.

As Sasuke felt himself being thoroughly kissed by the child form of his teacher, he was sure this had to shoot directly up to the top of his embarrassing moments list. The most irritating part of it all was that Kakashi was annoyingly talented at this sort of thing. Again, more reasons to despise both children and Kakashi.

Finally pulling apart to allow Sasuke breathe, Kakashi smirked before sticking his tongue out at the bewildered teen. Flopping himself back down on the mattress to face the opposite direction and pulling the sheet up to his chin, Kakashi called over his shoulder in amusement, "Payback for taking my new Icha Icha book away."

Sputtering, Sasuke glared murderously at the back of Kakashi's head. He could feel the strings of his self-restraint growing dangerously thin. Dear god. This was only the first day too. Frustrated, Sasuke rolled over to face the opposite direction again and angrily squeezed his eyes shut.

Oh yes, these next few weeks would be barrels of fun.

Naruto had to make a great struggle to force his way into Sasuke's apartment the next day. He had official documents from Tsunade! What the hell was Sasuke thinking, asking him to just slip the papers underneath the door? That kind of request simply made Naruto want to burst into the room even more.

After nearly half an hour of bickering with a door between their faces, Naruto had finally managed to squeeze in with the crack he had managed to keep by wedging his foot between the door and the frame. The first thing he did once inside was demand why Sasuke had refused to let him in.

"You don't have any new furniture, you didn't remodel, you're not naked," Naruto received murderous glares for that one, "and it's not like you're hiding a girl in your bedroom."

Apparently, Kakashi had chosen that very moment to wake up and call sleepily from Sasuke's bedroom, "Sasuke?"

Naruto was staring, and Sasuke did not like it. Unable to find proper words to defend himself, he simply glared back at his teammate. There was general silence. Then a wicked smirk curved on Naruto's lips. That meant the situation was about to get worse.

In a flash, Naruto had darted to Sasuke's bedroom door, yanking it open while exclaiming loudly, "Ne, Sasuke! What kind of girlfriend are you hid…ing…? Is that a kid? No way! Sasuke, you have a son?"

Sasuke suddenly felt a strong urge to beat himself over the head with a blunt object. Or, even better, beat Naruto over the head with a blunt object, then Kakashi, and then himself. It would be like another Uchiha clan tragedy. Except with blunt objects, only one Uchiha, and two idiots.

Rubbing the sleep out of his eyes, Kakashi looked up hazily with the blanks pooled around his legs. Seeing a splash of blond hair, he grinned lazily. "Ah, Naruto. Morning."

The blond teen blinked rapidly before staring down at the child with squinting eyes. "Strange," he muttered thoughtfully, "I don't remember ever meeting you. Although, you do kind of look like Kakashi-sensei. But Kakashi-sensei doesn't have any sisters I know of that Sasuke could have—"

A shuriken whizzed through the air towards the back of Naruto's head. Unfortunately for Sasuke, the blond dodged it and turned around to stick his tongue out at the dark haired teen.

"I don't have a son!" Sasuke exclaimed through gritted teeth, stomping over to the pair. Hitting Naruto upside the head and using his other hand to point at Kakashi's amused face, Sasuke demanded angrily, "What part of him looks anything like me, Usuratonkachi?"

"True. He's a lot cuter than you. Ah," Naruto said with understanding, rubbing the back of his head lightly. Teasingly, he grinned at his friend while nudging him playfully, "You've taken this kid to be your lover? I didn't know you were a pedophile, Sasuke!"

Only Naruto could have gotten away with his life after saying that to Sasuke, even as a joke.

Before Sasuke could pull out any more weapons in blind fury, Kakashi finally decided to intervene. He hopped out of bed the best he could with the overly long pajamas he wore and pulled down sharply on Sasuke's shirt until they were eyelevel. Cheerfully, he chastised while playfully patting the side of the teen's face, "Now, now, Sasuke. Be a good boy, and get along with your teammate, ne?"

"Shut up, Kakashi," Sasuke snapped, murderous gaze set on Naruto. "I'm going to kill him."

Ignoring Sasuke, Naruto bent over to examine the child with wide eyes. "Eh? No way. You're Kakashi-sensei? How'd that happen?"

"Long story," Kakashi replied with an easygoing smile while still calmly repressing Sasuke with a firm grip on the teen's shirt. "I'm staying with Sasuke until I get better."

"So you're recuperating," Naruto stated musingly, bringing his fist into his palm as the information clicked. "Makes sense. I was wondering why you didn't wake up w hen I first got to the door if you were here."

Kakashi continued to grin as he calmly tripped Sasuke and climbed up to sit on the teen's stomach. Still directing his gaze at Naruto, he replied, "Children need more sleep to grow."

It was then when Naruto promptly burst out laughing. The sight of a miniature Kakashi sitting on top of an angrily sputtering Sasuke was a better stimulus for outrageous laughter than swallowing an ostrich feather.

While still in a state of out of control laughter, Naruto retreated towards the door, leaving a stack of papers from Tsunade on the table as he left. Just before he shut the door behind him, he turned to grin wickedly at Sasuke, who was still pinned to the ground, "Don't worry about a thing, Sasuke. I won't tell anyone your lover is a kid that still tops you."

As the door clicked shut and Naruto strolled down the stairs whistling, Sasuke exploded, "KAKASHI IS NOT MY LOVER!"

This information simply went in one ear and out the other for Naruto. Oh, but Sasuke's neighbors had heard plenty.

Mortified, Sasuke brought a hand up to cover his darkened face. The world was officially over, and he could not get off of the ground. Once he removed his hand again to stare blankly at the ceiling, Sasuke felt a deep frown settle on his face. "Kakashi," he groaned in misery. "Hurry and grow up already."

In an attempt to comfort the dismayed teen, Kakashi leaned forward to ruffle Sasuke's dark hair. "There, there," he comforted with an amused grin. "At least I haven't gotten to the puberty stage yet."

And that was when Sasuke realized he had made the biggest mistake of his life.

Tsuzuku.

A/N: All right! So I'm sure we've all read all those Sasuke-becomes-Kakashi's-roommate-because-Kakashi-has-to-watch-over-him fics, so here's the exact opposite. 8D And as much as I love ItaSasu and NaruSasu (or SasuNaru), I'm putting out my epic KakaSasu fic. It's a change! But trust me, change is good. Anyway! This first chapter has been written for Sasuke's birthday, yay. Happy Birthday, Sasuke! (Emo-ninja-boy, you.)

This fic still has a bit of ways to go, so please let me hear/read your support/reviews if you enjoyed this! 8D Thanks for reading and please look forward to the next installment!