The new shape-shifter strike again, and Scott recruits a reluctant Allison to acquire a rare book in Gerard's collection.
Scott tries to keep Derek from creating new werewolves; Argent officially begin Allison's training; the new creature in town takes another victim.
The night before the new full moon, Isaac's father is murdered. When he's taken into custody, Scott, Stiles and Derek resolve to break him out before the Argents get to him first and before the newly bitten teen turns into a werewolf.
When Lydia goes missing from the hospital, werewolves and hunters alike begin a search to discover not only where she is, but what she's become.
Caught in the middle of a war between hunters and werewolves, Scott discovers one last clue which allows him to enlist both friends and even a previous enemy in order to stop the mysterious killings and win back Allison, the girl he loves.
While struggling with her family's secrets, Allison turns her focus to Scott and a Winter Formal dance. As the tensions between werewolves and hunters rise to a boiling point, Scott struggles to protect both friends and enemies while keeping his secret safe from Allison.
With startling revelations weighing on him, Scott finds himself scrambling to protect the people he loves -- including Allison, who begins to follow clues left by her Aunt Kate about her family history. Meanwhile, Stiles begins to close in on the mystery behind Derek's family.
