Episode 1
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.
Episode 2
Javi spends a couple of shifts at Firehouse 51. Kidd and Carver work together to help Carver's former boss. As Hawkins and Violet's relationship blossoms, Gallo turns his attention elsewhere.
Episode 3
Kidd recruits Carver, Capp and Tony to help prepare her new lieutenant's quarters. Severide and Det. Pryma pair up to work a police investigation. Firehouse 51 fights a movie theater fire.
Episode 4
Kidd gets a glimpse into Carver's chaotic personal life. Mouch and Herrmann receive an unexpected gift.
Episode 5
Firehouse 51 hosts a Halloween open house. Kidd and Severide help a young girl after she gets kicked out of her home.
Episode 6
Severide and Kidd investigate an explosion at a jewelry store. Cruz and Chloe take steps to make Javi a permanent part of their family. Gallo, Ritter and Mouch try to bond with Carver.
Episode 7
Herrmann is tasked with fulfilling a man's dying wish. Kidd reflects on her Girls on Fire program after one of her students graduates from the Fire Academy. A heckler harasses Firehouse 51.
Episode 8
Det. Pryma asks for Severide's help on a case involving explosives. Gallo and Carver clash after Gallo improvises on a call. Violet encourages Brett to start dating again.
Episode 9
Severide struggles with the cost of helping Det. Pryma with the Martucci case. Gallo campaigns for Herrmann to represent 51 at the National Firefighter’s Association’s Winter Conference. A familiar face makes a shocking return.
Episode 10
Det. Pryma's case comes to an explosive end with Kidd and Carver's lives in danger. Brett installs an infant safe surrender box at 51. Violet is determined to take Emma down.
Episode 11
Firehouse 51 prepares for their semi-annual firehouse inspection. Brett fights to save her paramedicine program. Commander Martin Pearce asks Severide for a favor.
Episode 12
Truck and Squad clash after a tense call rescuing a doomsday prepper. Herrmann struggles with Cindy's diagnosis. Violet gives Brett and Gallo dating advice.
Episode 13
Firehouse 51 helps Herrmann put on a school fundraiser. Carver's troubled brother comes to town. A grateful citizen is determined to thank Brett and Severide for saving his life.
Episode 14
An annoying floater takes a romantic interest in Violet. Ritter catches a local politician in a compromising position. Mouch and Severide help Trudy with an arson investigation.
Episode 15
Kidd, Seager and Carver investigate a fire at the city stables. Kylie clashes with some of the firefighters over changes due to budget cuts. Herrmann struggles to keep it together as Cindy's condition worsens.
Episode 16
Cruz feels the burden of his increased responsibilities. Kidd, Gallo and Carver get caught in the middle of a gang war on a call. Herrmann wrangles Trudy for help lifting Cindy's mood.
Episode 17
Mouch builds a classic firetruck model for the Deputy District Chief but needs some assistance from Gallo and Ritter. Brett and Violet encounter multiple victims with a strange set of symptoms. Cindy's chemotherapy results loom over the Herrmann family.
Episode 18
A familiar face returns to Firehouse 51 to serve with Kidd on a special task force. Mouch and Capp work to keep Tony safe, as he's days away from breaking the CFD's perfect attendance record. Old grudges resurface when Gallo reunites with a family member.
Episode 19
Boden, Ritter, Herrmann and Kidd work together to take down a local politician responsible for a chemical fire. After his aunt's accident, Gallo worries about their future.
Episode 20
Herrmann works on becoming a better man after Cindy's cancer journey. Kidd bonds with a homeless victim on a call. Kylie takes her firefighter exams. A harrowing call takes a toll on Brett.
Episode 21
Carver deals with the fallout of his arrest. Brett searches for closure with the baby she rescued. Capp weasels his way into the Firehouse 51 group chat.
Episode 22
Brett waits for life-changing news. Herrmann encounters a psychic with a grave warning on a call. Kidd finds a new lead on the Homeland Security case.
