First and foremost, in case anyone was on the fence about it, Theo is evil. His dastardly plan, all along, was to meticulously separate Scott from his pack, including best friend Stiles, so he could create his own pack.
The separation began with throwing heavy guilt on Stiles, planting in his head that Scott would never forgive or understand how and why he killed Donovan. Distraught, Stiles took it out on his beloved jeep when it died on him yet again. He tossed the offended wrench he used to kill Donovan into the window of the jeep. His guilt also pushed Stiles farther away from Malia, evidenced by their strained conversation when she picked him up after his jeep broke down.
Scott’s mother, Melissa, was called in to help with a dying Hayden. Liam is distraught and angry that Scott refuses to give her the wolf bite. Scott tries to tell Liam that she is too weak and the bite would kill her, but he will hear none of his answers.
Lydia is sitting with Parrish as they discuss finding out what he is. A conversation about a violent storm reminds Lydia about a conversation she had with Kira about a legend, the Wild Hunt, and she heads to the library. At the library, Lydia finds a book about a legend of dark figures and a wolf hound.
As Lydia prepares to find everyone and tell them what she found, Theo shows up at the library and begins to reveal his plan. He says he can’t let Lydia tell anyone and knocks her out.
The next is Malia. Theo shows Malia how he can morph from wolf to human and she wonders how he does that. Theo also tells her that he knows she plans to kill her mother and can help. He also tells her about Melissa taking Hayden to the hospital and they can’t have that. Malia follows him but he winds up locking her up in a storage room with one of the Dread Doctor experiments.
Scott gets a text from Lydia asking him to meet her in the library. He can’t find her but is surprised to see Theo holding mountain ash and spreading it around the library. Theo tells Scott that he has many tricks up his sleeve, including isolating Scott so he is out of the way for what he has planned.
Liam, unable to help Hayden, goes in search of Scott. He attacks Scott at the library when he finds him, fueled by the moon. Scott, unsure why he is weakened, realizes Theo put wolf’s bane in his inhaler. Scott is killed.
Mason finds Liam and tells him that Hayden is dead.
Malia, fighting for her life is saved by Braeden, who tells her that her mother knows about her plans.
Melissa finds Scott. She gives him CPR, telling him that she wants to hear him roar. He finally comes back to life in a roar.
As for poor Lydia, she wakes up in the lair of the Dread Doctors, listening to Theo’s dreaded plan. He taps into Lydia’s power and sees where Parrish was taking all the bodies. Taking a syringe from a tank with a specimen body inside, Theo takes Lydia with him.
Theo injects each of the dead bodies, considered failed experiments by the Dread Doctors, and revives them. He tells them they are his – meaning he now has a pack.
The Dread Doctors break open a wall in their lair to reveal a painting on the wall. Two figures are locked in battle and one is a hellhound.
Theo killed Scott, not Liam...