On Teen Wolf Season 6 Episode 17, Jackson and Ethan are attacked by hunters in London. These are amateur hunters, but somehow they managed to get their hands on wolsbane and kill quite a few omegas. Jackson and Ethan figure out that they had help from Gerard.
Mason, Lydia, Rafael, and Melissa were shot at the end of Teen Wolf Season 6 Episode 17. They are all alive and currently undergoing treatment in the hospital.
Scott decides to recruit people to join his fight against Gerard. He approaches Deucalion first, but Deucalion is now a pacifist. He tells Scott to lower his standards (even more), and so Scott and Malia ask Peter for help, who, shockingly, declines. Peter says Scott's not a killer, and to win the war, he will have to be.
Meanwhile, Theo and Liam are trying to figure out who attacked Scott's house. After torturing Gabe for a bit, Gabe realizes that they don't know about the other bodies -- the bodies killed by the spiders aka the anuke-ite.
They realize that one face of the anuke-ite is Aaron, and he's currently trying to find the other face. The anuke-ite's other face is a supernatural creature.
Malia meets with Peter, alone, to try to convince him to join the fight. She shows him, via the whole claws in the back of the neck trick, the affects of the anuke-ite. Sure enough, Peter is spooked. But it doesn't change his mind about joining up with Scott.
Scott and Malia go looking for another pack of wolves that have forsaken everything that made them human, hoping they win join the fight against Gerard. But when Malia and Scott arrive, the pack is dead, killed like the bodies Gabe showed Theo and Liam.
Lydia shows up, telling Scott and Malia that the dead Hellhound led her there. She realized that the hellhound wanted her to find the anuke-ite's other body. Sure enough, there's another skinless and faceless corpse.
The pack meets up and compares notes. Then, Peter shows up and officially joins the fight. Later, he tells Malia not to fall in love with someone who is going to die, aka Scott.
Jackson and Ethan stroll into Beacon Hills high and ask Monroe where they can find Scott McCall. She then kidnaps them and starts torturing them for information. Welcome back to Beacon Hills, guys.