The story of firefighters in Chicago.
Cast: Jesse Spencer, Taylor Kinney, Monica Raymund, Lauren German, Charlie Barnett, Yuri Sardarov, Christian Stolte, Eamonn Walker, Anne Lockhart, David Eigenberg, Joe Minoso, Randy Flagler, Don Kress, William Smillie, Steve Piper, Teri Reeves, Mo Gallini, Nicole Forester, Kathleen Quinlan, Anita Nicole Brown
Boden's chances for a promotion are met with potential complications, leading him to take matters into his own hands. Dawson and Casey don't see eye to eye on an important decision, while Kidd finds herself struggling to find time with Severide. Brett and Dawson respond to a tough call that quickly turns dangerous.
Boden takes a big step in the pursuit of a major career decision. Kidd becomes increasingly distrustful of Renee's motives with Severide. Herrmann has trouble bouncing back after a tragedy.
Lt. Severide is shocked when Rene Royce resurfaces; Casey comes up with a plan to help Chief Boden in his latest pursuit; Kidd regrets a decision she made regarding Severide; Herrmann clashes with Lt. Colannino over their son's basketball team.
Boden and Severide receive a surprise package after saving a girl from a car accident.
Casey grows skeptical of Cordova when a large amount of money turns up missing at the property of Mexican drug cartel.
Casey and Severide assist the FBI with an undercover mission; Kidd tries to help Severide come to terms with recent developments.
Boden has a lapse in judgment in the aftermath of rescuing a young boy. Kidd struggles to win the approval of Severide's mom after a surprise visit and Otis takes on new responsibilities at the firehouse.
The members of Firehouse 51 come to terms with one of their own being injured and deal with the temporary replacement.
Otis and Kidd respond to a call involving a residential fire only to head into danger when gunfire goes off in the house.
A domineering husband answers for his injured wife after Casey and Dawson respond to a car accident.
The firefighters help the police track down a bombing suspect.
The photographer whose pictures of Casey and Severide during a rescue make the front page of the newspaper chronicles a day-in-the-life story at the Firehouse.
Casey and Severide disagree on the best course of action following a time-sensitive rescue; Herrmann tries to entertain his daughter on "bring your kid to work day"; Dawson joins Brett on a spa getaway; Kidd's social life gets a boost.
Dawson and Casey do everything they can to locate Bria's whereabouts after discovering important new information. Lt. Severide reunites with Chief Grissom, an old family friend. Meanwhile, Cruz enlists the help of Brett and Mouch to create a new tool; and Kidd and Zach go on a date.
Dawson and Casey struggle to communicate; Brett and Kidd compete for the affections of a hazmat officer; Otis, Herrmann and Mouch search for the source of a stench that's making life difficult at Firehouse 51.
After saving a young girl, Dawson is forced to make a tough decision when she finds out the girl's father is addicted to painkillers. Herrmann loses his cool and gets into an altercation with a police officer after responding to a call. Otis and Cruz are on a mission to find out who Brett is dating. Meanwhile, Boden is skeptical when Donna's brother Julian unexpectedly comes to town.
Brett attempts to make a lifesaving decision in the field to someone near and dear to the firehouse family. In an effort to impress Lily, Otis scrambles to get everything together for the grand opening of Molly's North. Meanwhile, Boden becomes emotional following the rescue of a famous blues player from a burning apartment building and Dawson struggles to come to terms with how she has been dealing with her father.
After heroically saving a mother and newborn baby from a rooftop fire, Kidd receives surprising news: she's being transferred. Severide and Casey believe something is off about the turn of events, prompting them to investigate. In other events, Otis and Herrmann discuss the possibilities of taking over a rundown bar and Dawson's frustration with her father reaches a boiling point
Casey and Severide collide after Casey argues with him over the best way to save a teenager entangled in barbed wire. Casey looks to Boden for help, but realizes that he will have to fix the situation by himself. Elsewhere, Otis tries to convince Casey to participate in the beta test for an expensive piece of new firefighting equipment imported from Japan.
While running a secret errand, Dawson finds herself trapped in a collapsed parking structure; pressure mounts on Casey as he begins taking on additional duties; Kidd grows increasingly skeptical of Hope.
Lt. Casey gets off on the wrong foot with Sam Mullins, a temporary chief who is filling in for Boden at House 51 for the morning. When Casey later makes a risky move in an attempt to save a distraught man from jumping off a building, Mullins has a surprise that Casey does not expect.
When Boden learns that the school fire in which his wife was trapped was not an accident, he pressures Severide and Casey to find the cause.
With most of the squad still trapped in the warehouse fire, Chief Boden makes a risky last-minute decision to save them.