Squirrel Girl had been in a fight with a supervillain by the name of Kraven the Hunter. Logan knew of him only in the sense of knowing he was very good at what he did and that he usually went after Spider-Man.
At some point during the battle, Squirrel Girl had been affected by something, doubling over and throwing up mouthfuls of bile as Kraven made his escape. It wouldn't have been a major deal; it had ended in a stalemate- or so Squirrel's teammates assumed- but when they'd rushed over to check on her, she'd taken a chunk out of Ka-Zar, nearly getting mauled by Zabu in retaliation.
It'd been nearly a week of feral mutants waiting for an explanation, some hint of what had happened to their fellow, Logan among them. (He couldn't ignore that instinct in the back of his head that whispered, Something’s wrong.)
He'd received summons from SHIELD on the seventh day, requesting his presence aboard the helicarrier as a high-profile feral mutant. (He waited two extra days trying to get ahold of Spider-Man, his instincts whispering treasonous thoughts of Family. United front. Brother would know something is wrong. Spider could fix this, but Spider-Man is nowhere to be seen by anyone.) So he goes, arriving three days later to a group of SHIELD agents he couldn't get a good scent of, led by Agent Coulson.
wrongwrongwrong whispered angrily in the back of his mind, Logan has to exert more effort to keep his claws sheathed, giving an aura of relaxed. "What's goin' on here, bub?"
Coulson offers a reserved smile as his team escorts Logan somewhere he vaguely recognizes as towards the cells. There's a faint smell, probably nearly a week old, that his hindbrain insists it recognizes, but it's too muddled to put his finger on.
"I'm sure you've heard of what happened with Squirrel Girl?" Coulson starts, and Logan snorts.
"Who hasn't?"
"Yes, well, whatever Kraven shot her with brought out that feralness that's in the back of her brain; she was completely unaware of what happened while she was under, and the drug was completely out of her system before she even got back to the ship." Coulson continued.
"She back to normal then?" Logan sneers at Coulson's words, feral-ness; just because they had an extra set of survival instincts didn't make them uncontrollable murderous monsters.
"Not quite; it took her three whole days to wake up, during which she tried to kill anyone who got near her, and now, while she can't remember what happened and can now answer questions, she's still... feral." Coulson finishes, for lack of better words.
Something is wrong... wrongwrongwrONG! Logan's mind insists. Logan tunes out of whatever Coulson is saying as the faint scent gets stronger. They're almost to the cells, and- brother. Spider. He recognizes the scent moments before they step into the room.
Three glass hulk-cells are lined up in the room, the farthest from the door holding a small, hunched-over man in a worn brown jacket, huddled into himself as if hiding.
The middle holds a bright red-and-blue-suited Spider-Man, pressed up to the glass closest to the door and looking right at them when they walk in: "Wolverine, get out of here NOW!" Logan's arm hairs stand up and his claws are out before he even fully recognizes the warning. He doesn't ever glance at the third empty cell as he is already leaving. DEN, ESCAPE, DANGER Logan hadn't felt the need to question Spider-Man's warnings in a long time, and he'd always been better off for it; he wasn't about to start now.
He'd just have to hunt Kraven down himself.