"I have to go back," Stiles tries again, grinning against Derek's lips. "My dad gets back soon, and I'm pretty sure he suspects something."
"Just a little longer," Derek says, because Stiles looks way too good when Derek's holding him up against the wall, and he just has to kiss him again. And again.
Stiles makes a strangled noise and tries to shove him away. "Not that I'm not enjoying this-"
"That's fairly obvious," Derek says, and Stiles glares.
"Not that I'm not enjoying this, but unless you want my dad to come after you with his shotgun I need to get home before he does."
"Right," Derek says, and goes back to kissing Stiles's neck, since his lips is being a little uncooperative.
"He would," Stiles says; Derek thinks he might be pouting. "If he found out, I mean."
"Oh- Derek! No! Bad dog-"
Derek rolls his eyes but stops biting at Stiles's neck, even though Stiles is reeking of lust and it's starting to get to him. Instead, Derek leans forward until their foreheads meet and just looks at him.
"Creep," Stiles mutters, but he's smiling like he just can't help himself. "I'll see you later, okay?"
"Okay," Derek says.
Stiles pecks his lips and escapes out the door before Derek has a chance to trap him against it.
Not even ten minutes after Stiles left, Derek's starting to feel antsy. It reminds him uncannily of that day, six years ago, when he threw up in the school bathroom and everything felt wrong.
He pulls on his jacket and is out the door before he even thinks about it.
Stiles is lying by the side of the road when Derek finds him, covered in his own blood.
Derek looks at him for a second, two, three, unable to move.
"I'm going to die, aren't I," Stiles says, head lolling to the side so he can look up at him.
Derek shakes off the inertia and kneels down, looking for a wound, but they all seem superficial.
"St-Stomach," Stiles says, shivering. His lips are pale. "Inside. The car was driving pretty fast." He coughs again; there's an ominous rattle in his chest.
Derek drags his thumb across Stiles's lips, leaving his finger smudged with blood.
"With all this werewolf stuff, I never thought a car would be the thing to kill me," Stiles says, choking on a laugh. "Ow."
"You're not," Derek says suddenly.
"Not what?" Stiles says.
"I don't see you calling an ambulance," Stiles says. "It's getting pretty dark down here."
"I'm waiting for the right moment."
"But I'm not-"
Derek shushes him, palming his cheek. "Relax," he says.
Stiles's pained whimpers dissipate while Derek brushes a hand through his hair, his heartbeat stuttering in a way that makes Derek's chest feel tight and uncomfortable. He waits until Stiles is as relaxed as he can manage before he bites, hoping Stiles won't remember being in pain, or the too-long trip to Derek's house.
Derek keeps vigil while the bite takes. It seems to be taking forever, but he knows that's just a matter of perception.
Stiles lies on Derek's mattress, still and pale. Derek hasn't checked on his breathing for a few hours, can't bring himself to hear the whisper of air, all too quiet, but he can still hear Stiles's heartbeat in his ears.
Scott comes to visit the day after the first night -- Derek has lost count of the hours -- and Derek tells him what little Stiles said.
"It was a car," Derek says, fists clenching in anger. "All this time he was fine, and then... a car."
Scott sits next to Stiles for a while, clinging to his hand, almost as pale as his friend. Before he leaves, he stops in the doorway. "What if the bite doesn't take?" His apprehension and fear is thick in the air; the scent settles in Derek's throat until he thinks it might choke him.
"It will." Derek 's certain of it. Stiles was a better werewolf than Scott when he was human. He'll be better, now.
The seconds go by, then minutes, hours, days without a change.
"Derek," Scott says warily. Derek doesn't know when he arrived, but Sheriff Stilinski is with him. He doesn't look up from where he's lying, next to Stiles, waiting for the minutes to go by, waiting for a change; not the change, now, but any change.
"Son," Sheriff Stilinski says. He sounds gruff and is breathing heavily; like he has a cold, maybe. It's only when the sheriff puts a hand on Derek's arm that he realises he's talking to Derek, not Stiles. "You have to let go."
"He'll be fine," Derek says. "We just have to wait." Stiles feels chilly against his skin where they're touching, while Derek feels feverishly warm, like he'll evaporate if he lets go.
"Derek," Scott says, and he has to have a shitty consistution, because since Derek saw him last he's turned into a snivelling diseased mongrel.
"I just need more time," Derek says, and he doesn't recognise the strange emotion that permeates his voice, because he feels calm, calmer than he's ever felt before.
"There's no more time," Scott says. "It's over, Derek."
The sheriff pinches the bridge of his nose for a moment. "He can't stay here," he says eventually. "It's too drafty."
"I'm not leaving him."
"I realise that," the sheriff says. "But he's my son, and he needs- he needs to come home."
Derek's eyes narrow; they just want to take Stiles away from him. Stiles needs him. Still, there's truth to what the sheriff says; Stiles must be freezing, even tucked into the ash-stained blanket Derek's mother made unce upon a lifetime ago.
"Why don't you carry him out to the car?" Scott says, tilting his head to the side a bit to show his neck when Derek growls. "I'm sure you can go with him."
"Come on, son," sheriff Stilinski says, and he sounds even worse than before. He probably shouldn't be out of bed.
Derek watches them carefully, scents the air and doesn't sense anything but worry and fear. He gets up, lifting Stiles carefully from the mattress.
"Don't tell him I carried him bridal-style," Derek says, clutching Stiles tightly.
Sheriff Stilinski makes a weird noise, while Scott just smiles at him, off-kilter like he doesn't know how.
"I promise," Scott says.
Derek doesn't let go.