Deaton finds new information about the Dread Doctors while Scott and Malia come up with a plan to help their friends.
Scott and his friends follow Dr. Valack's advice; and experience strange effects as a result.
Stiles tracks a fugitive; and Liam plays wingman for Mason at a nightclub.
Mouch learns he may be a father. Dawson and Casey agree to take a break. The new Chief makes a tactical error and tries to put the blame on Casey. But Casey finds and unlikely ally in the case against him.moreless
There's a new chief at 51 while Chief Boden takes leave, and he brings with him a relieving firefighter who none expects they would every work with. The new chief's methods of leadership are quite different than the crews at 51 are used to ...moreless
Severide and Dawson conduct their own investigation into the fire that killed Shay. Casey and crew come to the rescue of one of their own. Mills takes a personal interest in a victim of domestic violence. Bowden grows closer to his father.moreless
Severide returns to the squad, but maybe too soon. Mills seeks out his paternal family while dealing with a mysterious health issue of his own. Herman seeks new partners in the bar. Dawson prepares to join a new house as a firefighter and Casey pops the question.moreless
Boden and the rest of the Firehouse 51 team deal with the explosion's aftermath in the Season 3 opener. Meanwhile, Casey searches for Severide, who's gone missing; Newhouse has surprising news about Mills' family; and Hermann and Otis make a decision about Molly's.moreless
Satomi's pack looks for protection from Scott and others. Malia and Stiles find out more secrets about the dead pool list.
Scott carries out a dangerous plan. Meanwhile, Malia confronts her past.
The school is under quarantine when a deadly virus hits it; Meanwhile, Braeden is shot.
Scott's position on the lacrosse team is threatened. Meanwhile, Stilinski investigates a murder.
The firehouse crew rally around each other after their recent loss, but will they come closer together, or will this break them apart? The Chief gets some BIG news.