Chaon Cross

Following the gutsy firefighters, rescue squads and paramedics of Firehouse 51. No field is more dangerous yet so exhilarating, but the personal lives of these men and women provide close competition.

Darden's widow publicly blames Severide for her husband's death and Casey makes a decision about his future with Hallie.

Lt Severide is targeted by an arsonist, Battalion Chief Boden clashes with Gail McLeod on the anniversary of Andy's death, Shay has suspicions, and Mari visits Mouch.

Pete discovers that Chief Boden knows more than he's letting on about the death of his father and Shay decides she's ready to be a single mum.

Tragedy strikes when a rescue attempt at a tenement building proves unsuccessful, leaving the men and women of Firehouse 51 affected by the loss of the victim.

Severide is on edge after the arson attack, fearing what might be in store next. Shay and Dawson, meanwhile, plan to party away their problems.