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.

While Scott tries to keep Isaac from engaging in a deadly confrontation with the Twins in school, Stiles attempts to prove his theory that the killings have nothing to do with werewolves.

During a bus ride to a cross country meet, Scott and his friends flash back to the events of a preemptive strike against the Alphas that has left several injured and possibly one or more dead.

As the danger begins to reach closer to Scott, threatening his trusted mentor and boss, Deaton, Kali and the Twins go after Derek.

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.

Under Deaton’s advice, Scott and his friends use an ancient but extremely dangerous ritual to help them both save the lives of the people they love and stop Deucalion from achieving his sinister goal.

Scott and his friends ponder catching the werecoyote before it is hunted down; an unlikely ally helps Derek and Peter break out.

On the night before Halloween, Mischief Night, a convicted murderer brought to Beacon Hills Hospital for surgery escapes, forcing Scott and his friends to step in to help when his unexpected target becomes clear.

Beacon Hills is under curfew from the power outage; the teens throw a blacklight Halloween party; Scott tries to earn Kira's trust.

Scott's friends pledge to protect him against an increasingly hostile enemy while Argent, Isaac and Allison search for answers through an old adversary from the Japanese Yakuza. At the same time, Stiles enlists Melissa's help in figuring out exactly what's going on with him.

Stiles goes missing; Scott and the others set off on a search; Lydia tries to master her new abilities.

Scott and the others try to prevent a disaster; Lydia and Allison seek out an unlikely teacher.

Scott and the others seek an important artifact; Stiles must make a decision about Eichen House.

Scott and Lydia join forces. Meanwhile, Stilinski faces a review board.

Kira faces an unexpected enemy.

Scott and Derek call upon their friends and allies to make a last stand.

On the eve of senior year, Scott and his pack deal with the arrival of a new enemy and the return of an old friend.