John Babbo

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

Casey struggles with his new responsibilities; Severide dreads the arsonist's next attack; Mouch starts campaigning; Dawson and Shay decide they need to get out more.

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

Severide comes across a boy in need of help while out on a jog; Boden and McLeod clash over the future of the firehouse; Mouch and Greg Sullivan debate on Otis' podcast.

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

Severide wants to implicate the serial arsonist; Dawson and Shay face the unexpected on a routine call; suspicions indicate Clarke is the mole; Mouch campaigns for union president.