Tracy Spiridakos

Kidd and Severide's honeymoon is interrupted by a dangerous person from their past; Kidd's former academy classmate joins Firehouse 51; Brett and Violet reflect on their relationships.

Mouch builds a classic firetruck model for the Deputy District Chief, but quickly needs some assistance from Gallo and Ritter. Brett and Violet encounter multiple victims with a strange set of symptoms. The results of Cindy’s chemotherapy loom over the Herrmann family.

Intelligence investigates armed bank robberies, which point to some surprising suspects; Lindsay is forced to make a decision in the heat of the moment.

A vigilante posts a video online of a man, previously locked up for statutory rape, being beaten and burned alive; Lindsay encounters some personal and professional problems.

Lindsay's mother, Bunny, becomes a murder suspect when her boyfriend is shot; high school students overdose on drugs; Lindsay finds herself up against the review board.

An entire apartment complex is forced into quarantine when cases of a deadly virus turn into an epidemic; P.D. chases a lead that could point to a case of bioterrorism, and Will gets dangerously close to the suspect.