Upon learning that Lydia is in danger, Stiles makes a plan to break her out of Eichen House; Theo has his own plans.

With graduation approaching, a supernatural force rides into Beacon Hills and crosses paths with Scott and his friends, while Liam discovers evidence of a new enemy in the high school.

The fate of Beacon Hills hangs in the balance as Scott and his pack face off against Douglas in a final showdown.

Scott and Malia prepare for battle while Argent searches for an old ally.