Episode 1 | Mayday

Firehouse 51 deals with the aftermath of the capsized boat rescue. Gallo, Ritter and Violet discuss plans for a side gig.

Episode 2 | Head Count

A video of Casey from the roof goes viral. Mouch sets up a Little Free Library at Firehouse 51. Herrmann breaks protocol.

Episode 3 | Counting Your Breaths

Griffin learns the truth about his father's death and reveals why he really came to visit Casey. Gallo, Ritter and Violet take steps to expand their microbrewery business.

Episode 4 | The Right Thing

Kidd spreads her wings as a lieutenant. Chief Hawkins rides with Ambulance 61 to learn more about Brett. Casey takes a trip out of town. A Ritter date night turns into an emergency situation.

Episode 5 | Two Hundred

In the show's milestone 200th episode, Casey makes a life-altering decision. Gallo, Ritter and Violet agree to an interview and photo shoot. Brett and Mouch launch the para medicine program. Cruz comes closer to fatherhood.

Episode 6 | Dead Zone

A major security breach in the city's computer networks forces Firehouse 51's senior leaders to take matters into their own hands. Severide gears up for an arson investigation.

Episode 7 | Whom Shall I Fear?

Gallo clashes with the new lieutenant temporarily filling in for Casey; Severide closes in on a dangerous and deadly arsonist.

Episode 8 | What Happened at Whiskey Point?

Severide and Herrmann clash over office space. Boden looks at Pelham's past as he considers making him permanent. Gallo's resentment of Pelham comes to a head. Brett and Ritter force Violet to confront her true feelings for Gallo.

Episode 9 | Winterfest

Gallo, Violet, and Ritter debut their microbrewery business at Winterfest. Brett prepares to present her paramedicine program to an oversight panel. Firehouse 51 gets in the holiday spirit.

Episode 10 | Back with a Bang

Stella Kidd returns to Firehouse 51. The team must work together to put out a potassium fire in a tunnel. After that incident, Ritter begins to worry about a young cop who witnessed the fiery death of a truck driver.

Episode 11 | Fog of War

On a call with Station 37, a firefighter is struck by a power line and decides to lash out after her injury; Brett is visited by Scott and Amelia; Violet gets a surprise envelope; the rest of 51 enters a contest.

Episode 12 | Show of Force

Boden, Kidd, and Severide work together to protect one of their own; at the Fire Academy, Herrmann meets an inspiring young man; talk of the annual CFD Gala dominates the firehouse.

Episode 13 | Fire Cop

Severide and Seager join forces to investigate a fire in a young woman's home. Pelham moves into 51's infamous office. Kylie helps Kidd with Girls on Fire.

Episode 14 | An Officer with Grit

Chief Hawkins helps Brett and Violet with a problem. Kidd is looking for a position as a lieutenant. Mouch and Herrmann are asked for a favor.

Episode 15 | The Missing Piece

Following an injury in the aftermath of an industrial fire, Severide and Seager work together to investigate an anonymous tip. Kidd searches for the right person to fill the open spot on Truck 81.

Episode 16 | Hot and Fast

Cruz forms a bond with a young immigrant boy he meets while fighting an apartment fire. Squad makes plans to prank the newest member of their team. Hawkins and Violet struggle to keep their relationship a secret.

Episode 17 | Keep You Safe

Severide and Kidd work with CPD regarding a suspicious car wreck. Hawkins and Violet's relationship is in jeopardy. Chloe and Cruz adjust to a new family dynamic.

Episode 18 | What's Inside You

Firehouse 51 must band together when one of their own is taken hostage.

Episode 19 | Finish What You Started

Firehouse 51 tackles a fire caused by a dropped jet engine and one of their own is accused of a theft related to the incident. Kidd and Boden disapprove of Kylie's potential new love interest.

Episode 20 | Halfway to the Moon

A family friend asks Herrmann for some advice on opening a bar. Tensions run high between Emma and Violet. Kidd struggles to keep her team together.

Episode 21 | Last Chance

Mouch and Ritter work together to solve a murder mystery; Severide and Cruz tackle a food truck fire; Gallo goes to see Hawkins about Violet.

Episode 22 | The Magnificent City of Chicago

The big wedding day arrives and Firehouse 51 welcomes Casey back to celebrate the joyous occasion. Emma's plans to replace Violet come to a shocking end.