Episode 21
The White Whale
A serial arsonist cold case is reopened when Lt. Severide finds a connection to a recent salon fire. Firehouse 51 celebrates a retirement party.
New recruits, evolving relationships, and high-risk rescues dominate a season full of change. The crew must earn trust again — both within the firehouse and from the people they serve.
October 3, 2018
Firehouse 51 is faced with a daunting challenge when an out-of-control blaze consumes a 15-story apartment complex, trapping victims on the top floors. Complicating the rapidly escalating situation, members soon discover that someone close to home may be one of the trapped victims. The crossover continues on Chicago Med S04E02 When to Let Go (II) and Chicago P.D. S06E02 Endings (III).
Episode 3
Thirty Percent Sleight of Hand
October 10, 2018
Chief Boden becomes increasingly skeptical of Assistant Deputy Commissioner Gorsch's motives, while Severide gets wrapped up in a difficult situation following the rescue of a child from a car wreck. Trying to fit in with the rest of the firehouse, Foster is tasked with doling out some personal advice to Cruz.
Episode 4
This Isn't Charity
October 17, 2018
Firehouse 51 is on high alert when a series of explosions rock the city. Herrmann adjusts to his new duties and Kidd gets a visit from an old friend.
Episode 5
A Volatile Mixture
October 24, 2018
Working alongside a journalist, Casey does some digging into the cause of a trailer park fire. Boden hits his breaking point while Mouch, Herrmann and Cruz work to figure out why Molly's isn't performing up to expectations.
Episode 6
All the Proof
October 31, 2018
Halloween is in full effect for Foster and Brett, who are summoned to a home where a prank has quickly turned serious. Gorsch continues his reign of terror on Firehouse 51.
Episode 7
What Will Define You
November 7, 2018
Severide faces some major adversity and Kidd is on a mission to help in any way she can. Following a car accident rescue involving a teenage girl and her young sister, a suspicious Brett has an unsettling feeling there is more to the story than what appears on the surface.
Episode 8
The Solution to Everything
November 14, 2018
Firehouse 51 is called in to battle a dangerous structure fire that places everyone in peril. Severide makes a big personal realization. Casey lends another helping hand to Naomi, the investigative reporter.
Episode 9
Always a Catch
December 5, 2018
Stakes are high when a massive car pile-up on the freeway impacts someone dear to the firehouse family. Brett and Foster encounter a harrowing call while Kidd and Severide find their relationship being tested.
Episode 10
Inside These Walls
January 9, 2019
A dangerous situation leaves Casey and Naomi in peril. Foster and Brett are in charge of planning a field trip visit to the station while Severide and Kidd go through tough times.
Episode 11
You Choose
January 16, 2019
Foster faces blowback after pointing out a doctor's oversight. Brett helps Casey look for a new apartment. Kidd prepares Tuesday the Dalmatian for the Fire Safety Dog Competition. A serious accusation is leveled against Severide.
Episode 12
Make This Right
January 23, 2019
When the firehouse is called to a motorcycle crash, Casey and Severide sense that the details don't add up and work to determine exactly what transpired. A rift develops between Mouch and Otis. Brett, Foster and Kidd work to secretly fix a dent in the ambulance bumper they believe they unknowingly caused.
Episode 13
The Plunge
February 6, 2019
Cruz leads the charge in getting the firehouse to gear up for the Polar Plunge. Herrmann has a hard time bouncing back after dealing with a tough call. Foster's personal relationships begin to interfere with her job.
Episode 14
It Wasn't About Hockey
February 13, 2019
Brett, Foster and Kidd take a road trip to Indiana and encounter an accident involving a boys' hockey team that leaves them scrambling and relying on their instincts to save the injured. The rest of Firehouse 51 competes in the annual chili cook-off.
Episode 15
What I Saw (I)
February 20, 2019
A spate of robberies comes to light after a firehouse lockbox key goes missing; Sergeant Hank Voight suspects a firefighter may be involved, and with Boden's support, he recruits Cruz to go undercover to help sniff out any suspicious activity. The crossover continues on Chicago P.D. S06E15 Good Men (II).
Episode 16
Fault in Him
February 27, 2019
Casey struggles after experiencing a narrow miss on a call. Otis wins a unique sporting opportunity in a raffle. Grissom turns to Severide for assistance when the mayor's office sends a task force to Firehouse 51.
Episode 17
Move a Wall
March 27, 2019
Tensions run high between Casey and Herrmann after the firehouse responds to an apartment complex fire. After discovering something extremely suspicious during the call, Kidd and Severide do some investigating and get CPD on the case.
Episode 18
No Such Thing as Bad Luck
April 3, 2019
Severide gets angry at Cruz when he feels his orders were disobeyed in the field. Boden reconnects with an old high school friend during a call to a house fire. Herrmann has issues when one of his favorite knick-knacks from Molly's goes missing.
Episode 19
Until the Weather Breaks
April 24, 2019
A horrible storm wreaks havoc on Chicago and impacts Firehouse 51 when the power goes off. A little boy mysteriously shows up at the station and everyone works together to uncover who he belongs to. Foster and Kidd argue about Severide.
Episode 20
Try Like Hell
May 8, 2019
Severide and Boden search to uncover whether arson was the cause of a fire at a hair salon. Mouch, Herrmann, Otis and Kidd make a startling discovery in tracking down the missing piercing nozzle from Engine 27.
Episode 21
The White Whale
May 15, 2019
A serial arsonist cold case is reopened when Lt. Severide finds a connection to a recent salon fire. Firehouse 51 celebrates a retirement party.
Episode 22
I'm Not Leaving You
May 22, 2019
Severide and Kidd continue to investigate Benny’s old arson case, unexpected news leads Brett to ponder a big decision and all hell breaks loose.
