Derek’s eyes linger after Stiles looks away, his body shifting restless, fingers clenching and loosing in a twitch across the exam table. The lie hangs bright and obvious in the air –– less in the absent hitch of heartbeat or the burn of nerves that don’t taste quite like embarrassment or like fear. Derek could explain those things away in context if he tried, but he can’t explain the way the words fail to line up with everything he knows he knows about Stiles.

“Becoming blind?”

“Yeah... terrified of it. Always have been.”

He wonders if it’s as obvious to Scott as it is to him, but the rest of the group’s already moved on, not missing a beat, focus shifted back to the problem at hand while Stiles re-centers. His pulse sharpens again and his eyes lift back to Derek, flicking up and away before moving back to Scott again, sliding seamless back into the conversation.

Derek shakes off the strangeness, and follows him.

.-

“Why did you lie in there?”

Stiles’ step falters on the question, and the resigned set of his shoulders tell Derek he’d been expecting this and hoping every bit as much to avoid it. Derek almost wants to take it back, tell Stiles is doesn’t matter, let whatever horror lives in the darkest place of Stiles’ heart lie there undisturbed... but this is too important.

He crosses his arms, keeping his tone and stance indifferent like that might make this conversation any easier.

“We need to know what’s coming, Stiles. When these things manifest, it’s not just going to be your fear anymore. It could threaten everyone.”

He’s not expecting the laugh that punches out of Stiles, harsh and thin and edged bitter enough to make Derek’s unaffected stance falter.

“Don’t you think I know that?”

Dark masks and fireflies float through Derek’s mind. A too-pale stranger with Stiles’ face and cold, ancient eyes. A huge lizard with paralyzing claws, and too-wet breaths as water threatened to pull them downward. A misshapen wolf with crimson eyes and spittle-laced breath, and an image of ghostly horsemen Derek had never seen, only heard of in Peter’s stories.

Derek could stab guesses at Stiles’ worst fears, could conjure up possibilities in Stiles’ quaking hands and nervous eyes as they darted out to the empty parking lot, looking for an escape before moving reluctant back to Derek. But he couldn’t know, and he needed to know, especially if it was something that could hurt the group.

...Especially if there was a way he could help Stiles prepare for it.

When it comes, he’s the one who’s unprepared.

“I can’t lose you again,” punches out rough and shaken, stunning Derek into stillness. Salt stings the air as tears well, and Stiles looks away on a wet breath, hand raking into his hair and tugging. “You were... dying and I walked away. I had to, there was nothing I could–– And then you were just gone afterward and I knew you were fine, I knew it was better that way but... fuck, Derek. It felt like you’d died some days.”

The tear tracks down and Derek feels his head shaking, arms falling from their faux-casual cross. The words are ringing through his mind, rattling around in a way that makes no sense and makes too much sense, echoes something too raw and honest inside him and he steps forward, “Stiles...” falling out soft, but Stiles is rocking a step back, shaking his head and swiping rough at the tear. Derek lets him retreat.

“My mom died in front of me.” This confession falls out soft, and Stiles’ shoulders shrink in against the sting of them. He looks small again, sixteen or years younger, and it takes an effort not to move in and shelter him from the sting of his own words. “And I just... I couldn’t do anything. Couldn’t save her. Do you know how that––” He cuts off, because he knows Derek knows. Derek understands that feeling better than anyone. It’s a bond Derek’s always wished they didn’t share.

Stiles shakes his head, blinking quick.

“Fuck, I can’t go through that again, ok? If these things are bringing our worst fears to life then I’m better off away from it, for everyone’s sake. What if it kills you because of me, because–– I can’t watch someone else I love die.”

The words hang. Stiles has gone strangely still suddenly. In the clinic, some young pup sets up howling.

“...You love?” Because Stiles had been talking about his mother, but he’d also been talking about Derek. About losing loved ones, and that...

Stiles’ breath hisses out, body tensing up defensive and challenging. His hands ball up, shoulders setting broad again, and it feels like every argument they’ve ever had when Stiles meets his eyes, daring him to doubt the revelations he’d just laid out.

Derek had learned a long time ago not to doubt Stiles.

“Don’t be an idiot,” he says, like it’s obvious. Like it’s some undeniable fact that Stiles loves him, fears losing him, that in all the nightmares of Stiles’ life, losing Derek could rest in anywhere near the same category as possession or dementia, or his mother’s death. But Stiles has always been afraid of losing people he loved, of not being able to save them... and Derek is one of those people. 

Derek is the person Stiles couldn’t look at while thinking about loss.

He moves forward a step, and Stiles doesn’t retreat this time, amber eyes locked with an expression that’s caught somewhere between challenge and pleading.

It’s one of the most terrifying moments of Derek’s life as he lifts his hand to Stiles’ cheek, and the most natural thing in the world once it’s resting there.

“I’ve died before,” he reminds Stiles, softly. “That’s not about to beat me. I’ll always come back... for you.”

“For me?” Stiles sounds breathless, doubt and hope warring as Derek’s thumb brushes over his tear-streaked cheek.

Derek tilts his head, warmth touching his eyes.

“Don’t be an idiot.”