Chaon Cross

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.

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.

Severide tries to prove his suspicions about the arsonist's identity, Casey gets accustomed to his new lifestyle, and Dawson goes on a date with a regular from the bar.

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.

McLeod pushes Boden toward an early retirement and chooses a potential replacement; all make known their disdain for the mole, and Shay enjoys a full social life.

The firehouse crew goes to the scene of a railroad accident; Boden must make a big decision about his future; Severide learns more about the woman he saw with his father; Shay and Dawson continue to butt heads.