The Dread Doctors promised Theo a pack. He asked them for more time, and told them that he needs Hayden alive. The Dread Doctors did not appreciate Theo challenging them.
Scott worries that he can't fight what's coming because his asthma is back. He shares all his fears with his new buddy Theo. In return, Theo lies about how Stiles killed Donovan. He tells Scott that Stiles just lashed out and kept hitting Donovan, and it took Theo pulling him off to get him to stop.
The chimeras aren't doing too well. Hayden is bleeding from the nose. A new girl, Beth, bites her nail and draws mercury, and the Dread Doctors kill her in front of Malia. Corey gets taken to the hospital for excessive mercury bleeding, but he decides to fight back. He turns invisible to hide from everyone, but the Dread Doctors kill him.
Stiles and Lydia search for the nemeton. Lydia brings Parrish into the mix, and he does lead her to it.
Theo covers for Stiles when his dad asks who killed Donovan. Instead of making Stiles look homicidal, Theo says he was the one who accidentally killed Donovan. Sadly, the damage Theo did between Scott and Stiles is bad.
The Dread Doctors inject Hayden with something, but she doesn't die, at least not immediately. Liam wants Scott to give her the bite, and he refuses.