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.

Casey falls under the thumb of a rogue cop after a horrific car crash, while new girl on the block Nicki pays Severide special attention.

Chief Boden comes under fire when the press blame him for the death of a homeless man, while Shay has a nasty run-in with her ex-girlfriend.

Casey loses his rag and comes to blows with Detective Voight, while Dawson's career hangs in the balance after her questionable conduct on a call.

Detective Voight plays with fire to get Lieutenant Casey to retract his statement and paramedic Dawson's career is close to flatlining.