On the eve of Senior Year, Scott and his friends find themselves facing the possibility of a future without each other, a next phase of their lives that might take them in different directions despite their best intentions. Little do they know that outside forces are already plotting to break the pack apart long before they ever see graduation; new villains that use a combination of science and the supernatural for a malevolent and mysterious purpose that will eventually pit Scott and his friends against their greatest enemy yet.
It's the eve of senior year and Scott and his pack deal with the arrival of a new enemy and the return of an old friend.
Stiles tries to prove his suspicions about a new classmate while Lydia helps a student with night terrors.
Scott tracks a dangerous new shapeshifter threatening Stilinski. Malia receives information about her mother's identity.
Stiles tries to track down a fugitive. Liam tries to play wingman to Mason at a nightclub.
In hopes of learning more about the Dread Doctors, the pack goes into Eichen House.
Scott and his friends experience strange effects after following Dr. Valack’s advice.
Stiles is suspicious about a new girl showing up and what her intentions are. Scott's plans to protect the newest victim are derailed when The Dread Doctors attack.
Scott and Malia get help to try to find Hayden and Liam. Deaton discovers something horrific about the dread doctors. Hayden and Liam will be faced with a life and death situation.
Scott finds himself turning to an unlikely ally for help. Stiles and Lydia attempt to find out the truth about Parrish.
Scott and his friends have to deal with what could be their biggest threat yet.
Scott and Stiles try to learn what is behind the mysterious infection that is killing the town sheriff.
Even without the support of his pack, Scott considers what the Dread Doctors' success means for Beacon Hills.
Kira and her mother make a journey to help Kira deal with her dark side. Meanwhile, Lydia is surprised at Eichen House.
As Scott tries to put his pack back together. Meanwhile, Malia and a new ally set out to rescue Deaton from The Desert Wolf.
Upon learning that Lydia is in danger, Stiles makes a plan to break her out of Eichen House; Theo has his own plans.
While trapped in Eichen House with Theo and the Chimera pack, Scott tries to rescue Lydia before time runs out.
Scott and the pack use a charity lacrosse game in a ploy to learn the identity of the Beast.
Scott, Stiles, Lydia, Malia, and Liam are trying to figure out how to defeat the Beast of Gévaudan that the Maid of Gévaudan, Marie-Jeanne Valet, faced in 1765. As Gerard Argent, recounts Valet’s story to Scott’s pack in hopes they can deduce the creature’s weaknesses.
With the identity of the Beast finally revealed, Scott and his friends are in a race against time to stop The Dread doctors from implementing their final plan.