The secret behind Derek's tattoo is revealed and the Alpha pack make their presence known. Derek and Isaac struggle to locate Erica and Boyd.

Allison and Lydia locate a possible clue to finding Boyd and Erica while one of Stiles' childhood friends goes missing.

With Boyd and Cora on the loose and under the influence of the full moon, Scott and Derek must turn to an unlikely ally for help.

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.