I'll start out by saying that I'm a happy Sterek shipper. I just think that Derek's tendency to growl "mine" is sort of unhealthy, and this fic is an exploration of that idea.

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The therapist's office always smells like plastic. Isaac doesn't know why, there is no more plastic in the small, neutrally decorated office than there is anywhere else. Part of him wants to think that the smell comes from her permanently artificial expression, preserved in a perfect sympathetic smile at all times, but real life doesn't tend to work out like that. If everyone who is artificial smelled like plastic, Isaac wouldn't be able to walk around without feeling like he's being suffocated by a grocery bag whenever he passes somebody on the street.

"So. Isaac," the therapist begins, leaning forward over her desk, hands clasped, looking at him with a practiced expression of attentiveness. "How has your week been?"

She moves so strangely. Isaac can practically see the mechanical joints at her waist, loosening and tightening the required number of inches so that the therapist can work through her array of practiced poses and faces, each designed to take the pressure off of Troubled Teens.

"It's been fine," Isaac says tonelessly. "I got a B+ on a precalc test."

"That's very good!" she exclaims.

Not that good. Calm down.

"Did you feel any anxiety about the test leading up to it?"

Isaac wishes he had never told her that he was prone to nervousness. It was the one and only detail about himself that he'd ever shared with her, and she'd latched onto it, deciding that it was the root of his "problem." Isaac doesn't even know what his "problem" is. The only reason he's going to a therapist in the first place is because his foster parents took his werewolf related absences to be drug and delinquency related absences.

Not that Isaac isn't a nervous person. He is. It could be something he was born with, or it could be something that sprouted like some sort of choking vine out of... everything that had come up in the last few years. He worried about Cam when he was dying, his father when he was depressed, his father when he was angry, his father's funeral, what it meant to be a werewolf, Peter, how Isaac would fit in with the pack, Scott, the Alpha pack, the homicidal fairies that came afterwards, the list goes on and on into infinity, always getting added to when Isaac tries to look at it. At the moment, the list is topped with "Derek Hale," in night-black, spiky cursive.

But he can't tell the therapist that. Instead, he says, "I felt a little. Not too bad."

He worries about Derek, though. He doesn't worry for Derek, even though he is sleeping with alarming regularity in the drafty remains of his burnt out house, even though he always seems to be wearing the same clothes, years after he'd shown up in Beacon Hills. Derek can take care of himself. No, Isaac worries about Derek. Isaac understands, better than most, that every person is equally capable of both good and bad. His father had hit and hugged at turns, Peter had been jolly and deranged, and Derek is the man that had dragged Isaac out of a life as burnt and dead as Derek's house, but simultaneously mercurial, violent, codependent, and possessive.

Derek doesn't direct the brunt of his vices at Isaac. Even if he did, that wouldn't be what has Derek at the top of Isaac's List. Isaac doesn't feel threatened by anything physical anymore. He just feels numb. Any hurts will all heal over anyway, like the scars were never there, or were at least sucked inwards from his skin to rest inside of his mind, adding to the collection.

What really has Isaac worried is that Stiles is on the other side of Derek's mood swings, his demandingness, his intensity. Stiles has been enduring Derek's negative attributes ever since he and Derek started... whatever it was they were doing.

It was simpler back when they would just pine from afar. Stiles stunk vaguely of arousal when Derek was around, and kept finding excuses to be nearby when Derek took off his shirt, as he did almost continuously when Stiles was looking. Meanwhile, Isaac would drop by Stiles' house and notice the faint scent of Derek just outside, like the last traces of footprints in mud before rain washed it away. He'd ask Stiles if Derek had come by, and Stiles would look at him in genuine confusion. Isaac was still rooting for them back then, so he didn't tell Stiles that Derek was probably spending his nights lurking outside Stiles' window. It was so hard for Derek to express anything, Isaac wasn't going to mess up his chances at achieving a relationship with somebody that wasn't based on mandatory pack ties. Even if Derek decided to be creepy about it.

But what Derek ended up achieving wasn't what Isaac would call a normal relationship by any means.

Isaac freely admits that he is not the best judge of "normal," but he doesn't think that "normal" starts with Stiles bounding up to him in the hallway, reeking like sweat and Derek and something salty that Isaac didn't want to name because as fucked up as it was, he sort of saw Derek as a father figure, and he didn't want to picture his father figure doing... that to Stiles.

Isaac wrinkled his nose, and Stiles laughed, the sound high and thin. "Yeah, the whole pack's been doing that all morning. I don't even care, man. It was awesome. Awesome. I totally did not see this one coming. Derek. Can you believe it? I mean he's basically a greek god, like, carved out of marble and untouchable except we totally touched. Like, all over."

"Wait, wait wait," Isaac held up a hand while the other rummaged around in his locker for his chemistry book. "How did this happen?" Isaac hadn't noticed Derek and Stiles getting any closer, just the usual lusty glances when the other wasn't looking. He wasn't sure if they'd even talked on their own since the fairy incident. Mostly they just saw each other when the pack met or there was some new crisis bubbling up like hot tar.

"Totally out of the blue," Stiles grinned, "he just hopped through my window and kind of pounced. Speaking of which," he held up a hand for a high five, "not a virgin anymore! Come on man, high five, you know you want to."

Isaac didn't particularly, but he obliged, slapping his hand lightly against Stiles' cold palm.

So they were fuckbuddies. Isaac could have dealt with that, even let the rather dubious consent that Stiles had given slide, if only they stayed that way. For a while, it was alright, even if it was incredibly strange how Stiles always reeked of Derek in a way that Allison never smelled like Scott and Lydia never smelled like Jackson and Erica never smelled like Boyd. Isaac didn't want to know what Derek was doing to make Stiles smell so strongly of him. He had suspicions, but again, father figure, father figure, stop it, stop it, put your fingers in your ears and hum as loudly as you can. Hum even when Derek stops talking in the middle of a meeting and drags Stiles to a back room somewhere in the house, hum louder and louder when the noises get louder and louder, echoing back from behind layers of charred timber to a pack of horrified werewolves with excellent hearing. Groans and moans and hitches of breath that could almost be pain.

It was awkward, and weird, and it sort of gave Isaac the heebie-jeebies, but Stiles seemed happy, and regular bouts of sex left him a lot calmer than he used to be. Derek, too, was more relaxed. His shoulders were set at less of a harsh parallel line to the ground, and Isaac imagined that his eyes looked less like they concealed a constant, burning flame just behind their blueish irises.

"Isaac? Isaac did you hear my question? How have your friends been doing?"

"Wh-sorry. Um, yeah, they're doing good. I've been hanging out at Scott's more, he's back together with Allison, and they do triple dates with Jackson, Lydia, Boyd and Erica. Happy and healthy, I guess."

Isaac doesn't talk about Stiles or Derek, because while he may be uncommunicative, he's never outright lied to Doctor Whats-her-name.

Because Stiles and Derek haven't just been really lusty fuckbuddies in a while, and at this point, Isaac honestly has no idea how either of them are doing, other than that they aren't happy and healthy.

In earth science, they were learning about gravity, because earth science was easily the most remedial science class that BHHS had to offer, and Isaac's grades weren't doing too well thanks to all of the long nights spent running around in the woods with the smell of blood in his nose and knives sprouting from the end of each finger. But they were learning about gravity, which was to say, the teacher was sitting in the back of the classroom reading as an outdated video, full of perms and synth music, discussed planetary motion on the projector screen. A voiceover came on, over-pronouncing each word and speaking with the exaggerated slowness, talking over a graphic of the earth, drifting around the sun while its moon circled it, following the earth wherever it went, forever on a 238,900 mile long leash. Something about it looked familiar to Isaac, and he realized that the dance that the planets were engaged in, so controlled and careful, was eerily similar to the display at dinner last night.

Pack dinners involved a lot of food, microwaved to within an inch of its life, crammed onto the Stilinski dining room table on the second Tuesday of every month. They also involved Stiles rushing from room to room, grabbing chairs, cutlery, dishes, food, more food, drinks, cups, napkins, anything to prepare for the meal. But at the latest pack dinner, his normal frenzy of motion was stilled, like the energy that once ran rampant through him had been pinned down. Stiles mostly stayed put, letting the other packmembers ferry supplies in and out of the kitchen. Isaac had been wondering if Stiles was sick, before he realized that Stiles was perfectly fine moving, as long as he was within an arm's reach of Derek, whose long arms were constantly wrapped around some part of Stiles, his hand, waist, shoulders, the back of his neck.

Everyone else just chuckled or cooed at the touchyness, but it made Isaac uncomfortable. It took a lot to slow Stiles down, but Derek had done it, and in doing so, a part of Stiles seemed changed.

"I see," the therapist replies. "A lot of your friends are dating each other. Do you ever feel left out?"

"Not really. I don't want to date someone just because my friends all are," Isaac says blandly. He didn't want to give her any more fodder.

He's telling the truth, though. Isaac knows that relationships have the power to buoy someone up and give them support, or at least give people someone to grope, but getting so close to someone can also be like having a hook curled into your flesh, attached to a string that the other person holds, and can pull on as much as they like. Isaac is fine with not having to deal with any of that.

Stiles, though. Sometimes Isaac isn't sure whether Stiles or Derek should go at the top of his worry list. Stiles has hooks lodged deep inside of him, until they are all that he can concentrate on. Isaac knows Stiles' grades are dropping because he zones out in class, thoughts elsewhere, probably following the string that Derek holds. It's eerie, the way Stiles' eyes glaze over, even in the middle of conversation. When he is paying attention, Stiles is witty and sarcastic, cutting and wonderful, but then he drifts off, and smiles to himself, eyes half closed. A joke between himself and Derek that he can't share, or a memory drifting across the surface of his mind, like a parade that demands attention.

It's worse when Derek was around. And he was around more often than not by that time. Picking Stiles up and dropping him off at school, even though his jeep was in perfect working order, in Stiles' room all the time, as Scott had complained to Isaac on many an occasion, following Stiles around when he did errands about couldn't keep their hands to themselves. It was escalating beyond the point of "cute," and into the realm of "not appropriate for children under thirteen." Stiles could no longer use chairs, and was pulled into Derek's lap instead. They twisted into two person pretzels on the couch, Derek curling around Stiles like a boa constrictor, trying to pull Stiles so close that he couldn't leave. If nothing else was happening at the time, their eyes were invariably on each other, Derek gripping Stiles' jaw and running an exploratory hand over his face like he'd never touched it before.

The therapist taps her pen against her jaw. "Well, Isaac, do you ever think that you're afraid of getting hurt if you grow too deeply invested in someone?"

"That's a leading question."

"It is. What's your answer?" Her eyes gleam dangerously.

"Maybe I am."

"Afraid?"

"Yes."

Her features contort into a vaguely sorrowful expression. "What is there to be afraid of?"

Stiles won't let anyone else touch him anymore. It started out slow, he just didn't shake hands or pat people's backs like he used to, but it became more obvious when he stopped participating in group hugs after lacrosse games, standing to the side like a lone tree on an empty plain. No more letting any of the girls hug him, either. His father is probably pulling his hair out, trying to find out what he had done wrong to make Stiles so reticent about coming near him. Isaac knows that it's because Derek can't stand smelling anyone else on Stiles. It isn't a werewolf thing. Jackson, Boyd, Erica and Scott are fine with extra smells, they don't lock away their boyfriends and girlfriends from other people's touch. Maybe Derek had lost so many people that he won't risk Stiles getting any further away from him. Maybe he's just nuts. Either way, he growls at anyone who sits too close to Stiles on movie nights, the bone-crumbling, knee-shaking growls of an angry Alpha that sets any werewolf within hearing distance on edge.

When a pair of traveling hunters came through town, and the pack went to try and talk them down, Derek kept Stiles held behind his back through the entire duration of the tense conversation. One of them -the tall one with mournful eyes and floppy hair- tried to see who Derek was hiding away, and Derek wolfed out, baring his teeth and flashing his eyes. It was hard to hear what he said from between the fangs, but Isaac could have sworn he heard "mine."

Isaac is fairly sure that's illegal, owning another person. Not that Stiles and Derek aren't breaking plenty of laws already, Stiles still being several months away from eighteen and them fucking like obsessive, possessive rabbits. The claim of ownership bothers Isaac more, though. Stiles had been so radically free before Derek. It made him impulsive, perhaps a bit spazzy, but there was a beauty in it that is gone now.

After Boyd and Scott stepped forward, apologizing profusely, the hunters calmed down and went on their way, but with no help from Derek, who had retreated into Stiles' hair -grown out because Derek wanted it that way- whispering fiercely into it, declarations and insistences that Isaac tried not to hear because they made him so very uncomfortable.

Isaac laughs dryly. "There's so much to be afraid of."

"Oh yes?" the therapist asks calmly. "Like what?"

Isaac wants to wipe her calm, knowing look away. He wants to make her break under the force of everything he fears, to make her see something other than another identical case of a traumatized boy, a battered son.

"Losing yourself. Losing everything that made you you because somebody else took you over."

Stiles is turning up at school less and less, preferring to sneak around to any private place he and Derek can find and fill it with the scent of sex. He had a 4.6 once. Now, Isaac was overhearing Mr. Montgomery say they might have to bump Stiles out of Precalc.

"Doing things not because they make you happy, but because you desperately want to make someone else happy, whatever it takes."

It's even rarer for Stiles to come to lacrosse practice, even though his muscles are growing enough that he could probably make first line if he really tried. When he does show up, you can see that his skin has become a morass of purple and blue. Mouth sized circles along his neck and collarbone and chest. Lines the length of fingers wrapping around his hips. Isaac had asked about them once.

"Derek has a marking thing," Stiles said vaguely, caressing over one of the stains on his skin.

Isaac continues, raging against the emptiness in the therapist's eyes, "and not being able to leave it behind! Getting so caught up in the intensity of everything that you don't know that you're hurting yourself."

"Stiles, do you ever think that Derek's kind of... much?"

"Naw, that's just who he is." Isaac noted that Stiles didn't explicitly deny the charge. "Besides, I can never do better than him, you know?"

Then Stiles' eyes clouded over, and he was lost to the rest of the conversation.

"Well," the therapist says, her face implacable. "That was quite an outpouring of emotion."

From Isaac, maybe. The therapist sits unaltered. Isaac gets out of his chair abruptly, pulling away from the cloying comfort of the cushions. He feels jittery and wrong, like gravity is pulling on him ever so slightly sideways. "I'm leaving."

"Wait, we were making so much progress," the therapist recites.

Isaac feels like laughing. Also like going to visit Stiles. He has the strangest need to check on him, the feeling you get after watching Old Yeller, like you have to go hug a dog.

Stiles' house looks empty from the outside, the windows dark even in the encroaching twilight. If Isaac knocked on it, it would probably echo like some old, hollowed out thing. A bone sucked of marrow. But he knows it's occupied. If the sound of muffled heartbeats didn't tip him off, the sight of Derek's camaro and Stiles' neglected, dusty jeep did.

Isaac opens the front door. He knows better than to expect Stiles to come downstairs to answer it. Taking a cautionary sniff, Isaac determines that any fucking had finished hours before, and that he will probably find Derek and Stiles upstairs, close to sleep.

"Is that Isaac?" comes Stiles' sleepy murmur.

Derek hums in approval.

Stiles shouldn't have been able to know who it was from upstairs. There's too much distance, too many doors and walls in between Isaac and Stiles for a human to be able to identify someone by a few rogue footsteps, or Isaac's cool, musty scent.

Vibrating with anxiety, Isaac climbs the stairs, a sense of foreboding stalking him as he goes.

"Should I send him away?" Derek asks lightly from behind the door.

"It's fine. He'll be the first to know!"

When Isaac comes inside the room, he doesn't need Stiles' glowing eyes, or his excited, babbling explanation to tell him what he already knew. Derek's arm is curled like a vice around Stiles' bare stomach where they still lie in bed, and he runs a tongue across Stiles' neck like Isaac isn't even there, and he thumbs across the bite right over Stiles' heart, and Isaac knows that Derek had gotten what he always wanted.

Stiles will never be able to leave.