Whilst Stilinski investigates a murder, Scott has his place on the Lacrosse team threatened by a freshman.

Scott attempts a dangerous plan to draw out The Benefactor. Malia confronts her past.

Stiles works on tracking down a fugitive; Liam tries to be Mason's wingman at a nightclub.

Scott and Stiles try to learn what is behind the mysterious infection that is killing the town sheriff.

After a shocking attack leaves the pack reeling, Scott sets out to recruit reinforcements.