It takes a while for Stiles to realize something's going on. It's not that he's unobservant, it's just that, look, a lot of weird crap happens in Beacon Hills. Which means he's a little oversensitive to major weirdness—werewolves, Hunters, and kanimas, oh my!—and a whole lot desensitized to low level weirdness.
So he notices it early on but doesn't think much of it beyond, “Huh, weird.”
Then Scott gropes his ass and licks his neck after a spontaneous game of pick up lacrosse. After Stiles nearly jumps out of his skin, a dozen other little things from throughout the day fit together to form a picture that's really disturbing.
He locks himself in the house that night, freaking out, only to have about a dozen different people come to his door (or, in Jackson and Scott's cases, his window). Stiles peers through the window by the door at one point and sees a veritable altar's worth of offerings in the form of food, flowers, cards, and other random things.
Stiles throws up in the bathroom and then sneaks out the back door.
For a number of reasons, Derek is not Stiles' first choice for help in this situation. The idea of forcing some kind of unnatural attraction to Stiles onto Derek is horrifying. Peter Hale told Stiles about Kate Argent, about what she did, how she manipulated and used a teenage Derek to get what she needed to slaughter the Hales. If making friends and random people hot for him is sickening, doing it to Derek is a million times worse.
There's also Stiles' heinously inappropriate, unrequited, and long-lasting crush to consider as well. The crush doesn't need any false hope, or any more fodder for embarrassing and guilt-laden, yet very hot, fantasies. It's got more than enough, honestly, just with the pool thing alone, and it's already severely affecting Stiles' ability to actually date anyone. All he's good for is casually hooking up with guys who superficially resemble Derek and that just makes things worse.
The thing is, though, that Stiles needs information, and then probably to get back to Berkeley, where this started.
“Stiles, you don't have a choice,” Lydia says over the phone. She's at MIT and didn't come home for Spring Break this year because she's trying to finish her undergrad degree a year early. Stiles thinks about her in the aftermath of Peter Hale, of how her mind wasn't her own and what it did to her, and is profoundly grateful she's not here. “You need information and he has that library of books he salvaged from Fresno last year.”
“Lydia. Lydia, I really think he would kill me when he came out of it. I know I mouth off a lot about him killing me, but this time I'm serious. I'd kill me for this!” He gasps for air. “I'm subverting people's wills. I can't--”
“Calm down! Right now!”
Five minutes later, Stiles is as calm as he can get, which isn't anywhere near normal levels of calm.
Lydia makes a noise of approval. “All right, listen to me. First of all, this is not something you're doing, it's something that was done to you. Remember that. Second of all, this is what you and Derek do, Stiles. One of you walks through a steaming pile of shit, tracks it all over the others' house, and bullies the other into helping.”
Stiles chokes; Lydia is never that crude. “Steaming pile of—what kind of people are you hanging out with out there?”
“I've been up for sixty four hours, trying to make the best use of the scant amount of time I have with the supercomputer. You're lucky I'm coherent at this point.”
It takes him two hours to get to Derek on account of having to go into the woods, circle almost half of Beacon Hills, and then come out as close to the latest creepy hideout as possible. Stiles wasn't too keen on walking the streets of Beacon Hills where there are people.
Unfortunately, there are people in the hideout, too. Or, well, werewolves, but whatever.
“Jesus Christ, Derek, a little freaking help!” Stiles calls out, trying to push Isaac and Boyd off him. They're sniffing and licking at every inch of skin they can find and Stiles is panicking, and he's not even sure whose hand is trying to shove down the front of his pants.
A moment later, Stiles hears a roar. Boyd and Isaac freeze, then scramble away from Stiles, dropping to the floor and crab walking away. Stiles turns and Derek is behind him, eyes red, fangs flashing. “Leave,” he snarls at the werewolves. And they do. Fast. Then Derek grabs Stiles' arm and glares. “What the hell did you do?”
“I saved a witch from a mugger.”
Derek makes a sound that's the equivalent to a facepalm. Stiles twitches.
“Say, you're not experiencing a brand spanking new unnatural and uncontrollable attraction to me, are you?”
Derek stares at him. “I'm really, really not.”
Stiles sags slightly in relief. “That's awesome.”
“Are you sure she was a witch?” Derek asks later that night. Derek's new hideout is the basement of an abandoned bank in the old part of town. He keeps the library in one of the vaults. Right now the two of them are sitting on the floor, piles of books scattered around them. Derek holds up the one he's looking at, showing Stiles a picture. “Could it have been her?”
“I know how to recognize fae, and I think I'd remember meeting someone who looks like that--”
Derek turns the page to another picture. “This one sometimes looks like this.”
“--unless she looked like that at the time,” Stiles says faintly. “Which she did. Crap.”
“Please tell me you're kidding.”
Stiles claws at his own face. “I wish I could.” He points in the general direction of the center of the main drag, which is clogged with people. So many people. “Her store is over there.”
A muscle ticks in Derek's jaw, and Stiles doesn't blame him for it. They stopped for gas on the way here, and Derek had to rescue him from the bathroom, where he'd been cornered by about nine different truckers, not to mention the waitresses from the diner next door, and random parents who'd stopped during road trips. Stiles doesn't think Derek was really prepared for just how strongly people are reacting to Stiles.
“Is it just me or are they getting a little violent?” Stiles gasps from the ground five minutes later. Derek is braced over him, keeping the mob of people around them from getting their hands on Stiles.
Derek grunts. “Obsession'll do that.” Then Derek rocks over him, and around the protective curl of one of Derek's arms, Stiles sees a few sets of feet dangling mid-air, which means that a bunch of people have just piled onto Derek to get at Stiles. Derek hunches his head down and Stiles sees his eyes go red, his teeth grow. “Two blocks over, right?”
Stiles swallows. “Um, yeah?”
Derek's smile is feral and not a little terrifying. He wraps an arm around Stiles' middle, then surges up, more wolf than human. The people who'd piled on him tumble to the ground, and then Derek leaps through the mass of people, Stiles dangling from one arm, and runs.
They slam into the small herb store, Derek shutting the flimsy door behind them. He sets Stiles on his feet and looks him over. “You're bleeding.”
Stiles follows Derek's line of sight and sees a set of nail marks on his forearm. They're shallow, they sting now that he's noticed them, but they're not life threatening. “I'm also bruised across about forty percent of my body, but whatever. I can worry about that later.”
Derek narrows his eyes and then his hands are all over Stiles, poking at his arms, his sides. Stiles winces and tries to twist away, which makes him wince more, but he keeps trying because, yeah, that crush. “You've got a cracked rib, Stiles!”
Stiles maybe landed a little hard when one of the mob tripped him to the ground. “I've had worse. Just, focus, okay. We need to find--”
Stiles startles badly, almost toppling over. Derek grabs his arm, jerks him upright, and then steps in front of him. The fae looks like the first picture Derek showed him, with the ears and the eyes and the glowing. Honestly, if she'd looked like this instead of like a sort of frail elderly lady, Stiles would have left the mugger to her not-so-tender mercies and not gotten involved. Fae are vicious creatures.
Stiles waves at her awkwardly from around Derek. “Hi, hello. Remember me?”
The fae nods. “I do, yes. Are you enjoying your gift?”
In front of him, Derek goes frighteningly still. Stiles can almost taste the waves of furious disbelief wafting off him. “You accepted a gift. From a fae.”
Stiles kicks the back of his ankle. “No!” He looks at the fae again. “I, uh, told you no thanks were needed. Ma'am. Miss? Lady. I was happy to help, and clearly, my help was entirely unnecessary because you're a total badass fae. I probably got in your way.”
She tilts her head to the side, the look in her eyes eerie and alien. “You gave me your favor. I returned it with one of mine.”
Derek reaches back and grips Stiles' wrist, tight, and Stiles gets the message to tread carefully. Which, he's not an idiot. He's not going to actively try to piss off a fae.
“That's—thank you.” Stiles clears his throat. “It's, you know, an honor? I just--”
Derek growls. “What was the favor?”
She blinks; it seems to take two minutes for her to do so. “He was sad. Lonely. One he loves is unattainable for him.” Stiles feels the blood drain from his face. He's really tried very hard not to admit to himself that his crush is actually more than a crush. “I provided him with options.” She looks away from Derek, to Stiles again. “Among your kind, there must be another who would suit you.”
This. This right here is why there are entire books warning people about favors and gifts from fae.
“That was very thoughtful,” Stiles says weakly. He's not sure if a fae can understand the concept of rape at all, much less mind rape, and he's not sure it's worth it to try to explain it to her. “But, it's—I'm human. I'd like to find someone on my own. The way my kind normally do. Also, your favor, while extremely generous, is sort of causing a lot of problems for me.”
“That wasn't my intent.”
Stiles nods his head. Vigorously. “I know! There's sort of a species gap going on. So, with no offense meant, could you possibly retract your amazing favor?”
The fae's eyes go distant, her expression something like thoughtful. “I can't leave a debt unpaid, a favor unasked.”
“In return for his help,” Derek says, and how the hell he's managing to talk with his jaw clenched like that, Stiles doesn't know, “could you undo the favor you initially blessed him with, and fix the injuries he's sustained?”
The fae is silent for a moment, and then she smiles. Stiles' breath catches in his chest, because she's suddenly the most beautiful creature he's ever conceived of, that has ever existed. “A lovely solution, lupus.”
The next instant, they're no longer in the store. Instead, they're on the street, in front of where the store...is not, and never has been, given there's no room for it. The fae has changed appearance and is glamoured to look like a small old woman once again. Around them, the mob of people—who must have followed them—are moving off like nothing has happened. Stiles touches his ribs, gently, and it doesn't hurt. The cuts on his arm are gone.
“No debt will lie between us,” the fae says, then just disappears.
Lydia calls when they're driving back to Beacon Hills. It's been a very silent trip. Derek's actually more tense than he was during the whole mess, which makes no sense, and Stiles has bitten his tongue out of self-preservation and the fervent hope that Derek won't ask him about why the fae did this.
“Is everything okay?”
Stiles leans his head against the window. “Yes, it's all fixed.”
“And is Derek trying to kill you?”
“No, he's not, just like you said he wouldn't.” Though, huh, that raises a question. “And thanks for talking me through my freak out.”
Lydia sniffs. “Whatever. Don't call me again until break's over. I've got too much to do.”
Then she hangs up, because she's Lydia and that is just what she does. Stiles snorts and puts his phone back in his pocket. He catches Derek staring at him intently, his expression a familiar one that indicates he's trained his freaky senses on Stiles, and frowns. “What?”
Instead of answering, Derek pulls over on the side of the road and turns the car off.
“Okay, was I wrong? Are you actually going to kill me? Because you weren't even affected, which I'm kind of curious about, but that means you have no reason to kill me.”
“You're not in love with Lydia.”
For about ten seconds, Stiles is completely and gloriously unaware of where the hell this segue came from. In that time, he says, “What? Of course not. That was, like, years ago and wasn't even--” Then he realizes what prompted it, and where it's going. He chokes on his own spit and frantically scrambles for both his seatbelt and the door handle. He gets the seatbelt undone, but Derek snags his hand before he can get the door open.
“And I never said I wasn't affected,” Derek goes on.
Stiles gapes at him. “What? You—yes, you did. I asked you and you said you really weren't!”
Derek undoes his own seatbelt with his free hand, then twists in place. He pins Stiles still with a stare that's—holy god, it's heavy or something. Wild. “Who are you in love with, Stiles?”
“No one!” Stiles says, panicked.
Derek smiles, smug and placid all at once. “Lie.” His hand tightens on Stiles', not hard enough to hurt, but enough to remind Stiles he's there, touching him, can probably feel Stiles' pulse racing. “Who.”
Stiles thinks he might pass out. “Don't--”
Derek leans forward, nostrils flaring, and says, deliberate and slow, “Is it me?” Even though Stiles doesn't say anything, Derek's entire face flashes with satisfaction and his eyes drift close briefly before he leans in more. He puts his mouth right to Stiles' ear; Stiles makes a small, wordless sound. “It isn't new, or unnatural, or uncontrollable.”
Suddenly, Derek is back in his seat, watching Stiles carefully, and Stiles is reeling and confused, and hardly able to make sense of what the hell just happened. Beyond the fact that, apparently, his body gave away his secret love for Derek without his permission, that is. But, wait—Stiles asked—and Derek—not new or unnatural or uncontrollable.
Stiles jacknifes in his seat and stares at Derek, eyes wide, mouth hanging open.
“Now you're getting it,” Derek murmurs, a curious mix of fondness and mockery.
“Why didn't you say something?!”
“Why didn't you?” Derek counters. It must be rhetorical, though, because he climbs across the bucket seat on top of Stiles, knees pressed into the leather on either side of Stiles' thighs, hands on the back of the seat, bracketing Stiles' head. “All those people, today, suddenly desperate to get at you, to lay hands on you, to make you theirs—I've wanted to do it for years.” He grinds down and Stiles' dick goes from status quo to completely in the game in the matter of seconds. “I've wanted you for years.”
Stiles' hips jerk, his back arches, and he wants to just step off the cliff, to go with this, but-- “Want? That's it? Just want?”
Derek's head snaps down, like a snake striking, his nose and open mouth pressing against the side of Stiles' neck. “Not just want.”
Stiles swallows dryly. “Love?”
Derek licks a line to Stiles' jaw, then cups the side of Stiles' face, and looks down at him. “Yes.”
Stiles doesn't just step, he jumps, off the cliff.
Hours upon hours later, Stiles stumbles out of Derek's bed—he's actually had an apartment for over a year, though he rarely uses it and only took Stiles there when Stiles refused to have sex on the marble floor of an old bank basement—sore and sticky and ridiculously happy and in desperate need for the toilet.
When he's washing his hands, he happens to glance up at the mirror. He freezes when he sees the fae's face in it. He looks frantically over his shoulder, but she's not behind him. She's just...in the mirror.
She smiles, says, “Now no favor lies between us, young human”, and vanishes from the mirror.
Stiles blinks, thinks about how if she hadn't tried to give him that gift, he and Derek might never have gotten here, then dries his hands and goes back to the bedroom. He wakes Derek up by jumping on top of him. “Come on, let's go again.”
Derek looks up at him blearily, but with interest edging into his expression. “Unbelievable. You're insatiable.”
“Then it's a good thing you've got werewolf stamina.” Stiles grins. “Besides, we've got time to make up for.”
He just laughs when Derek flips him onto his back and pins him to the mattress.