"The thing about zombies," Stiles says.
Jackson, Lydia, and Scott all groan. Allison looks intrigued, though, and Derek's rolled his eyes but hasn't said anything, so Stiles forces the hurt down and focuses on the fact that not everyone has already written him off.
He's still gathering his thoughts, in the middle of turning to face Allison, when Isaac says, "No, no, let him continue."
The room goes silent and Stiles gapes -- everyone else does, too, he notices through his surprise. Stiles frowns, eyes narrowing in suspicion, as he looks at Isaac. "Uh. What?"
"Zombies," Isaac says. "The thing about them?"
"Oh, for god's sake, don't encourage him," Lydia mutters. Derek rubs a hand down his face and makes a tactical retreat to the kitchen.
The glare Isaac turns on Lydia is honestly impressive. "With Beacon Hills being the way it is, it's only a matter of time," Isaac says, tone on the verge of biting. "And since no one else in the pack is doing the research and making plans, we should listen when Stiles does." Isaac gives Lydia a smile with fangs, and adds, "You know, since he's doing it for us."
"Okay, scarf boy," Stiles says, glancing around. Allison's barely holding back a laugh, Scott's frowning in confusion, and Jackson's flushing pink with fury. Lydia doesn't look that much better, face pale and mouth opening to argue back; Stiles doesn't think he's imagining the ring in the air that usually precedes a banshee tone of voice, so while Stiles is still a little weirded out by the honest interest and the underhanded compliment -- he thinks that's what that was, anyway -- he's willing to do pretty much anything to cut Lydia off before she gets going. "The thing about zombies," he says, hurriedly, "is that humans are persistence hunters, right? Persistence hunters and pursuit predators. Even if zombies don't have higher brain functions, I think it's safe to assume they'd hunt the same way we do. So we need to know if their blood stops circulating or if their immune systems die when they do --"
"-- Because then their own feet will drop off," Isaac says, nodding slightly as he considers it, "either due to lack of circulation or disease. Doesn't matter if they're the fast moving kind or the slow Romero kind, it's hard to keep going with no feet or some infection like gangrene."
Stiles, still a little unnerved but now ready to take advantage of a willing audience, nods repeatedly. "Their teeth -- all that bacteria we normally have, well. I've got notes," he says, gesturing at his backpack, left in a pile with all their shoes and the rest of their bags. "Do you, uh," he half-asks, though the wariness disappears completely when Isaac gets up from where he's been sprawling next to the couch and holds out his hand to Stiles.
And that's where it all begins, really.
Years later, lying on the ground under the light of a full moon, their pack playing around them, Stiles will ask why Isaac was so willing to play along.
Isaac laughs a little, looks away for a moment, then says, "You had the peculiarly rare ability to make Jackson's blood pressure rise no matter what you said, Derek was looking for an escape, and Lydia was trying to force The Notebook down our throats again." He pauses, Stiles pokes him once, twice, makes a little inquisitive sound in the back of his throat, and Isaac sighs and says, "It really was only a matter of time, especially with you bringing it up apparently out of nowhere."
Stiles goes still. "Especially if I was? Why especially if I was?"
"Stiles," Isaac says. "You always know. It's what you do."
"I didn't think anyone noticed back then," Stiles replies, quiet and faltering in the face of the trust and encouragement threaded through Isaac's words. It's true, he did always know, gift and curse both, but it was a long, hard road to get to the point now where people take him seriously, plenty of severed friendships and discarded opportunities left along the way. "You -- even then? Even when everything -- when everyone --."
Stiles trails off, eyes fixated on the sky, mind reaching as he fits this piece into a puzzle that's always had a few empty spots, and -- yeah. Even back then, Isaac trusted Stiles' little feelings, the directions his research took him, the unexplainable instincts. All the others, save Derek, a time or two, and Allison, later on, ignored him until it was basically impossible: Stiles half-dead, the headless corpses of two vampires on fire right behind him.
He'd been kidnapped and no one had come for him. Stiles, even through three days of increasing blood loss and despair, bided his time and tried not to give up hope. When the opportunity presented itself, Stiles pushed down the delirium and weakness long enough to get himself free. Desperation gave birth to magic, which lit him up from the inside: a raging fire that swept through him and took off the vampires' heads in one clean strike before giving him the flames to set their remains on fire. The magic didn't die down with the lack of enemies, though, and by the time the pack got to him, his own spark was eating through him, fingernails and hair starting to disintegrate into dust.
Stiles thought he knew his pack, thought they knew him, but when he met their eyes, he could feel their disappointment, their judgment, their fear. His own broken heart was enough to dim the power and only his pride and anger gave him the willpower to wrestle the magic back down and under control.
"Scott said something funny to me once," Stiles admits, "a few months after the vampires. He said you were the one who tracked me down."
That never made sense to Stiles; he always assumed it was because Isaac had the more sensitive nose and knew him, by that point, a little better than the others. Before he'd been taken, Stiles had talked about the kind of places a vampire would hide, and he knew, waiting alone in that cave, that no one had listened because no one came for him. That was the last straw, really, even before the magic ignited and burnt him up from the inside.
But now, slotting this information into place, it suddenly makes sense. Isaac knew where to find Stiles because he'd listened. It only took him so long to actually get to Stiles because -- "How long did it take you to convince them to come after me?"
"Sixty-four hours," Isaac says, quietly.
Stiles was only gone for seventy-five hours, at the end of it. Just over three days, and Isaac had known after eleven hours, maybe less if he'd started searching by himself before going to the pack for aid.
"You never told me," Stiles says, then shifts, rolls onto his side so he can look at Isaac. "I know why, don't worry. Well. I probably know why."
"Things got better," Isaac says, "for both of us. Quickly, too. Faster than I expected."
Someday, when they talk about it, Stiles will reach out to take Isaac's hand in his, will think about spending three months in the hospital and heading off to spend two years in Ireland with only Isaac at his side, will think about the fractured relationships that never healed, will think about Derek and Scott and his father -- and then Isaac will pull him to his feet and lead him into the house. They'll go to bed, curl in tight together, and fall asleep, still hand-in-hand, to the sound of the pack howling on their nightly rounds.
Now, here, in Beacon Hills, Stiles and Isaac leave the pack house and talk about zombies. It's the only reason they all survive unscathed when a necromancer tries out an untested spell three weeks later and raises every corpse within sixteen miles of the nemeton.