While Scott tries to keep Isaac from engaging in a deadly confrontation with the Twins in school, Stiles attempts to prove his theory that the killings have nothing to do with werewolves.
During a bus ride to a cross country meet, Scott and his friends flash back to the events of a preemptive strike against the Alphas that has left several injured and possibly one or more dead.
Stranded at a motel for the night because of the postponed cross country meet, Scott and the others suffer strange experiences that cause them to believe members of their own group may be the mysterious killer's newest targets.
As Allison begins to suspect someone dangerously close to her may be involved in the murders, Scott and Stiles conclude that Lydia's rising talents may be their best bet to solving the murders.
Trapped inside an evacuated Beacon Hills hospital by a powerful storm, Scott and Derek must defend themselves against the Alphas while trying to figure out how to save Cora's life.
With the threat growing far more personal and time running out on innocent lives, Scott is forced to make a difficult choice in order to save both friends and family while, at the same time, Derek and Peter try to figure out how to save Cora's life.
Under Deaton's advice, Scott and his friends use an ancient but extremely dangerous ritual to help them both save the lives of the people they love and stop Deucalion from achieving his sinister goal.
