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.
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.
The team needs to use other resources when an attempted robbery leads to the death of a Navy lieutenant and the entire city suffers a major blackout.
Jane and Maura must unravel an old ghost story to solve a double murder at a hospital, and Angela convinces Frankie to stop avoiding Kent.