Derek stares at the half-finished puzzle in front of him for a few long seconds, then shakes his head clear. "This is dumb."

"Really?" Stiles says. "I thought you liked puzzles."

"Like a million years ago," Derek grouses. "I'm not a baby."

"No, yeah, of course not," Stiles says reassuringly. "And you weren't ten minutes ago, either. What do you like now? Xbox?"

Derek rolls his eyes. "Do I look like Laura?"

Stiles doesn't answer.

"Video games kill your brain cells," Derek says, authoritatively.

"And strengthen your reflexes," Stiles offers.

"My reflexes are fine," Derek lies. "I read. Literature."

"Soooo you're definitely my least favorite you," Stiles says.

Derek doesn't dignify that with a response.

"Lemme guess, you've memorized the complete works of Shakespeare." Stiles smirks. "Unabridged. Oh my god, do you, like, quote it? I lied, you're my favorite."

"No," Derek says, neck prickling, determinedly not looking at Stiles at all, mostly. He accidentally finishes the puzzle in record time. "Shakespeare's overrated."

"Now we're talking," Stiles says, leaning forward. "Please tell me you've read something not compiled from rare antique manuscripts, untouched by human hands. Like... I don't know, Artemis Fowl? Yeah, that's exactly the kind of thing you'd like. Like a stuffier, up-its-own-butt Harry Potter."

Derek shrugs. "I like Harry Potter."

"Oh, thank god," Stiles says.

Derek jerks under the cold fire of Kate's taser, teeth grit tight, fighting not to howl. There's no guarantee who it would call—a strange alpha to kick him when he's down, or Scott McCall, dying in some attempt at amateur heroics. Either way, it isn't worth it.

The scream claws its way up anyway, barely caught between Derek's teeth, every inch of him shuddering, Kate stepping around him, firing again, again.

"Wouldn't be the first time," he says, neck cramping as he fights to glare up at her.

And then she's gone, and the pain is gone, replaced by the sharp scent of antiseptic, cool barely-raw skin, and Stiles Stilinski, talking animatedly about Albus Dumbledore.

Derek stares.

"Whoa, hey, oh my god," Stiles says. "You're—you again." He sidles closer, lays his hand over Derek's like it's the most normal thing in the world. "And I'm real, I swear. See? Ten fingers."

"Congratulations," Derek says. His head pounds under this new bright light, half of him still caught with Kate, still stiff with phantom pain. He scans the little room through halo vision. "Where the hell am I?"

"Oh! Deaton's," Stiles says. "Y'know, the clinic. How much do you remember?"

Derek snaps upright, barely wincing. "He's the alpha."

"What? Oh—shit, no, I was wrong," Stiles says. "The alpha, right. that was like—god, it feels like forever." He shakes his head, adds hurriedly, "But yeah, no. Like half a year. Three quarters."

"Can you maybe try to, I don't know, make sense?" Derek snaps. His skin is itching, crawling, pain throwing off all of his senses.

"Right, wow," Stiles says. "Extra sarcasm Derek. It's been a while."

Derek exhales through his nose. "What," he says.

"And no question marks!" Stiles says, but quickly tacks on, "No, ignore me, this is just—It's been a really weird morning."

Derek waits.

"Someone de-aged you into a teenager," Stiles says in a rush. "And your body's trying to go back to normal, so your age isn't really the most predictable thing in the world. Like, even more than usual."

"And," Derek says.

"And," Stiles echoes blankly.

"Why are you here," Derek clarifies.

"Oh, that," Stiles says, a little too brightly. "So, the long answer starts about fourteen million years ago—"

"The short answer," Derek says.

"I'm here to make sure you don't wolf out and get stuck that way," Stiles says. "Because I'm your anchor. Or whatever. Oh, and the last thing you remember probably isn't actually the last thing, it's just—the last thing… you… remember," he finishes lamely.

"You're not my anchor," Derek says.

"Check again, bud," Stiles says.

If he's lying, Derek can't hear it, but that doesn't mean much. His own heartbeat is so erratic, he has to strain to detect another.

"Why would you be—" He stops. Stiles looks like he might cry.

What is happening.

"So I'm trapped here," he says.

"Trapped is a strong word," Stiles says, voice catching just a little. Derek carefully doesn't notice. "Secure, how about that? Y'know, you don't shift and permanently lose your humanity, I don't lose my mind thinking you're dead again, it's win win."

"You don't even know me," Derek says, baffled.

"On the contrary," Stiles says. "I know enough yous to start a baseball team. Like the most adorable baseball team ever, by the way."

Derek stares at him, nostrils flaring. Stills.

"We're not," he starts.

"We don't have to talk about it if you don't want to," Stiles says quickly. "Y'know, not that it is even…" He ducks his head, face pinking. "I know a lot of Dereks, okay. I only started figuring that stuff out with one of them." He considers. "Or—two, maximum. So we could just be buddies."

"Buddies," Derek says. His voice echoes back alien.

"Bros," Stiles suggests. "Homies. Friends. It doesn't have to be bae every day, is what I'm saying. And uh, even if you did want this to be a thing, I'm gonna need some really compelling evidence you're not gonna randomly age down and scar my dick for life. Like, that's non-negotiable."

"I don't—" Derek says, shaking his head. The room keeps shaking long after.

"Hey, hey, c'mon," Stiles says, hovering worriedly over him. "Don't even—Okay, friendly ban on eye rolling so i know when i'm actually losing you, okay? Just—don't you pass out on me, I'm serious. I will lose my actual—Can someone please do something?"

The last line is a shout, clanging all the way around Derek's skull before it settles. His arm is on fire, his shoulder, but a comfortable numb is eating through the pain, stealing it away.

He can't convince himself to care.

This isn't his life. This isn't how it works.

When Stiles is backing up over him in his Jeep on the way to fix Scott a sandwich, Derek'll know this is real. This? Watching over him, trying to protect him? Talking about being—He must think Derek's an idiot.

Stiles wouldn't want that. No sane person would.

The room's already fading all around him.

"How are you bleeding right now?"

Something in Derek's chest goes Stiles, goes anchor, goes limp, even though that's impossible. Derek doesn't move.

Can't move.

Someone must've moved him, but he can still feel her. Can still feel her dying. His hands are clean, his clothes, but they shouldn't be. They should be thick with black blood, lead-heavy.

"Are you—" Stiles says, then, "What happened? Swear to god, you look away for a second."

So he doesn't know. Derek doesn't know if he's relieved or weighed down even heavier by the impossible concern in Stiles' voice.

He lifts his head just long enough to flash a warning.

Blue eyes. So there. So this Stiles guy can just stop caring so much.

Derek's shoulder burns, and his eyes sting, but that's fine, that's exactly right. He needs to remember.

Warm fingers over his cold cold skin, peeling the t-shirt from his mauled shoulder.

"Peter did this to you," Stiles says hoarsely.

But that's not true. That's not close to true.

"It wasn't Peter," Derek says. "It was—That alpha hurt her, I h-had to—"

"Hurt him back," Stiles realizes. "An alpha? You really thought you'd win that fight?"

He's staring at Derek now, fingers still grazing his scarred shoulder, stupidly gentle.

"What, were you trying to get yourself killed?"

Her heavy body going heavier, the way his wrists ached under it. The raw horror on Peter's face.

Derek remembers and remembers and remembers.

Stiles eyes widen. "That was rhetorical, Derek. Oh my god."

Derek flashes his eyes pointedly.

"I don't give a—" Stiles starts, and clamps his mouth shut, swallows. "You're not a killer. You're not—There are people who'd be dead a thousand times over if not for future you."

Derek's brows drag together. "What?"

"You heard me," Stiles snaps. "But if you want to be some self-sacrificing emo jackass, fine. I guess my best friend'll just bleed to death in the woods two miles from his house while you're figuring out the tracklist to your apathy mixtape. And FYI, using more than two Nine Inch Nails songs in a row is cheating."

"Someone's hurt?" Derek says, struggling to stand, to shrug Stiles' hands off without feeling like he's being torn open all over again. He can't just stay slumped here warming up like he deserves that, he has to—If there's pain to take, even if there isn't—

"He was," Stiles says. Rethinks. "Will be. And you drag him away from the hunter shooting at him, and then you save his life about fifteen other times. And mine."

"In the future," Derek says skeptically.

"Sort of," Stiles says. "Think time travel meets, uh, 50 First Dates. Wait—Did that movie come out yet?"

"What movie?" Derek asks blankly.

"50—Forget it," Stiles says. "Just—don't. Just don't, man. Please. Believe it or not, your continued existence is actually kinda integral to my sanity."

"Do you even know what my eyes mean?" Derek asks.

"Do you?" Stiles challenges. "Because I know some people who did not fall under the stone cold killer category and got 'em anyway. One person," he amends under Derek's skeptical stare. "Still. Kanimas aren't killers, they're just tools. And I mean, if he got murder eyes just for being someone's pet—" Stiles' hand twitches almost imperceptibly. "Then the only reason we're not Care Bear Stare twins is that I'm still human."

"You're not making any sense," Derek says.

Stiles exhales sharply. "Dude, I'm trying. With every single one of you, I'm really—But it doesn't matter what this you thinks, does it? No offense, but you're history. Literally. Not even in chronological order, just—And you're not gonna remember me! Any of you."

"There's just one of me," Derek says, completely bewildered.

"You bet," Stiles says tiredly. "Just do the aging thing again, okay? Aim for older. I'll be... here."

"Do you trust me?" Stiles asks.

"Of course," Derek says, unthinking, before remembering, raising his hands, fingers splayed.

"You're counting your fingers," Stiles says. "You're actually—How old were you the first time we kissed?"

Derek's mouth goes dry. He stares up at his fingers again.

"Are you hurt?" Stiles presses. "Before, you were—I think it was the bullet, the wolfsbane bullet, but then you were eight and you just slept for six hours and Deaton said you were healing, and then—"

"We kissed?" Derek says, still processing. None of this makes any sense. He was on a bench of the BHH locker room, and then... But that doesn't make any sense either. "Stiles, what's happening?"

"You still don't remember," Stiles says slowly, deflating. "Any of it. Mexico? Kate?"

"Kate?" Derek says, alarmed. "What're you—"

That was a dream, that had to be.

"She's gone," Stiles says, hugging his knees to his chest. "Again. Braeden took care of it."

"Braeden," Derek says. "The mercenary?"

"Cora's girlfriend," Stiles is already saying. "Deaton's niece. I—Maybe?" His eyes clear; he nods. "Yeah yeah yeah, the mercenary."

"Cora's girlfriend," Derek says. "My sister Cora?"

"Turns out they're, like, soulmates," Stiles says, a little dully. "Finding each other half a world away, saving each other's lives. It's this whole thing."

"Cora's seventeen," Derek says.

"Braeden's twenty," Stiles says, shrugging. "And Cora spent three months tracking her down after Braeden got her back to you and took off."

"And we kissed," Derek says again, uncertainly. Stiles' dejection is leaden, numbing. "More than once."

Stiles frowns, drags his hand through his hair. "I thought it would be easy. Or—easier. Once you were you again, y'know? That you'd just remember everything."

"Once I was me again," Derek says.

"You were deaged," Stiles says wearily. "Sixteen, just before—you know. And Kate—She's gone now, I swear, but she took you to Mexico. Me and Scott and Malia and Lydia finally found you there, bought you back—"

"Bought me," Derek repeats, not sure he's heard right.

"Not from like a brothel or anything, don't worry," Stiles says. "These other hunters found you, it was a—a retrieval fee."

"And then we kissed," Derek says.

"Not then," Stiles says, irritated. "Months passed. Things happened." He swipes at his eyes, stands up briskly. "It doesn't matter."

"It doesn't—" Derek echoes, not comprehending, but something in him curls in on itself, keening.

"You're not him," Stiles says, shrugging. "C'mon, everyone's outside."

There's a big stupid puzzle on the floor all finished, and Derek breaks it all up in five seconds. Stupid sky, stupid trees, whole stupid picture turning into just blue and green and brown and so there, so there.

He pulls his knees close against his chest, arms locking them in place, and glowers at everything.

"Shi—Whoa," says the man standing over him. "What's wrong?"

Derek swipes at his eyes.

The man crouches down beside him, eyes worried. "Was someone mean?"

"You're mean," Derek retorts, and sniffs. "I don't like you anymore."

Real shock widens the man's eyes. "What'd I do?"

Derek's stomach keeps twisting, and looking at the man makes it worse. "I don't like you anymore," he says again. It feels better, after. He draws in a shaky breath, eyes barely watering. "You're stupid."

"Oh," the man says. He sounds sad. Derek hugs his knees closer. "I still like you," the man says.

"You're a liar," Derek says, chin trembling.

"I'm not," the man says. "I'm not lying. I swear." He frowns. "Does it sound like I'm lying?"

"No," Derek admits. His stomach hurts really bad.

"Well I'm not," the man says. "You don't even know, man."

Derek unlocks his limbs sullenly, starts collecting side pieces.

"Here," the man says after a while. "Some got scattered." He unloads the pile gathered in half his folded-up shirt, just stands there, looking lost.

"You can help," Derek says charitably, tapping two pieces into place.

"Yeah," the man says, blinking lots of times at once. "Yeah, okay."