第 4 季 共 23 集
播出时间：2015年10月14日
第 1 集 Let It Burn
播出时间：2015年10月14日
Casey is placed in a dangerous situation while working undercover to bring down a trafficking ring being run out of Nesbitt's club. The squad's high turnover rate results in an unwelcome surprise for Severide. Dawson recognizes that her life is about to change. A new candidate makes an unusual first impression. Residents band together to protest a drug den in their neighborhood.
第 2 集 A Taste of Panama City
播出时间：2015年10月21日
Boden's job is on the line pending an internal investigation. Severide adjusts to Patterson, his new commanding officer. Dawson shakes things up at the work. Casey searches for important evidence in his investigation of Nesbitt. Herrmann tries to keep the peace with Molly's new neighbors.
第 3 集 I Walk Away
播出时间：2015年10月28日
Evidence that seems to exonerate Boden may not be enough. Brett and Chili find themselves in a precarious situation. The team responds to a stuck elevator in a hotel. Jimmy Borrelli's older brother wants him transferred to a different house.
第 4 集 Your Day Is Coming
播出时间：2015年11月4日
The squad members come together to support one of their own. Herrmann tries to figure out how to reopen Molly's after it gets shut down. Severide digs deep into the arson investigation.
第 5 集 Regarding This Wedding
播出时间：2015年11月11日
Boden offers to host a wedding at the firehouse after a fire destroys the original location, but it doesn't sit well with Chief Riddle, who also butts heads with Dawson over her ability to perform. Severide fights for his old position. Capt. Patterson finds himself torn between leadership and his colleagues.
第 6 集 2112
播出时间：2015年11月18日
Boden's new neighbor asks him for a favor that could have serious repercussions. Severide is upset when he's treated like a candidate by Patterson. Cruz is visited by a gangbanger who knows his brother. The team responds to a call that involves an 18-wheeler; and is thanked with tickets to see Rush.
第 7 集 Sharp Elbows
播出时间：2015年11月25日
Boden suspects his neighbor is setting him up; Severide, who's still on probation, receives a surprise visit from his father and also learns something about Patterson that could be a game changer. Romance blossoms at a fire department gala.
第 8 集 When Tortoises Fly
播出时间：2015年12月2日
Boden believes Maddox is behind Serena's accusations. Severide reaches out to Jamie, who's Maddox's lawyer, in an attempt to help. Patterson questions whether Boden can remain chief. Brett and Chili suspect that a man passed out in a garden is connected to a previous call. Otis has problems with his social calendar.
第 9 集 Short and Fat
播出时间：2015年12月9日
Patterson fills in for Boden, who's trying to clear his name. Severide learns where Serena may be hiding. Herrmann and Otis give Freddie a job that keeps him close by. Jimmy and Chili draw more attention then either bargained for.
第 10 集 The Beating Heart (I)
播出时间：2016年1月6日
Herrmann fights for his life after being stabbed; Cruz hits the streets to find Freddie. Mouch proposes to Trudy.<br />
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The crossover continues on Chicago Med S01E05 Malignant (II) and Chicago P.D. S03E10 Now I'm God (III).
第 11 集 The Path of Destruction
播出时间：2016年1月20日
A tornado threatens Chicago. Chili makes a major mistake, which causes Brett to report her to Boden. Otis asks Dawson to help him solve his women troubles. Severide assists a Department of Homeland Security agent.
第 12 集 Not Everyone Makes It
播出时间：2016年1月27日
Freddie's father begs Herrmann to forgive his son's assault. Casey discovers that a makeshift shelter housing people displaced by the tornado may close. Casey attends a fund-raiser at the request of an alderman. Dawson and Brett experience repercussions after telling Boden about Chili's erratic behavior.
第 13 集 The Sky Is Falling
播出时间：2016年2月3日
The team responds to a mass shooting; Casey investigates the missing money from the fund-raiser. Jimmy agrees to represent the firehouse in a boxing match against the Chicago PD's 21st District. Chili's behavior continues to be an issue for Brett.
第 14 集 All Hard Parts
播出时间：2016年2月10日
Severide confronts Chili about her erratic behavior. Members of the firehouse rally around Casey, who they think would make a great candidate for alderman. Jimmy squares off against Antonio in the first annual "Battle of the Badges" boxing match.
第 15 集 Bad for the Soul
播出时间：2016年2月17日
The team responds to a suspicious call from a neighboring firehouse; and welcomes a new firefighter, though her addition has repercussions. Casey moves forward in his run for alderman.
第 16 集 Two Ts
播出时间：2016年2月24日
Casey reconsiders his run for alderman after he's targeted by a propaganda campaign. The squad responds when a man is trapped inside of a burning car. Trudy's nerdy brother plans Mouch's bachelor party. Jimmy and Brett investigate a kidnapping on their own.
第 17 集 What Happened to Courtney
播出时间：2016年3月30日
Severide and Cruz find a child's remains inside a chimney while investigating a possible carbon monoxide leak inside a home. In other events, Casey braces for the worst in his run for alderman while Alderman Becks continues to bad mouth him to the press.
第 18 集 On the Warpath
播出时间：2016年4月6日
Sylvie witnesses a murder and is threatened by the shooter not to go to the police. Firehouse 51 jumps into action when a fire breaks out at a restaurant and traps several people inside a vault. Mouch starts to get cold feet.
第 19 集 I Will Be Walking
播出时间：2016年4月20日
Casey steps up to help a teenager being bullied by a gang; Severide bonds with a detective’s son after her life is threatened; and Kidd and Herrmann go head-to-head in a test of bar knowledge.
第 20 集 The Last One for Mom
播出时间：2016年4月27日
Firehouse 51 unites to help a young boy in tragic circumstances. A high-powered political consultant helps Casey navigate a potential scandal. Cruz makes a mistake that nearly costs him his life.
第 21 集 Kind of a Crazy Idea
播出时间：2016年5月4日
Dawson saves a young boy from an apartment fire. Kidd's idea for Molly's doesn't go as hoped. Severide hits a wall while advocating for new fire masks. Cruz and Brett utilize a secret weapon to get Otis to see Dr. Halstead take a blood test.
第 22 集 Where the Collapse Started
播出时间：2016年5月11日
The team responds to a building collapse that's trapped more than a dozen people. Dawson's quest to foster Louie is aided by a familiar face. Otis, who's on medical leave, meets his temporary replacement. Severide and Kidd continue to see each other. Casey is at odds with Antonio.
第 23 集 Superhero
播出时间：2016年5月18日
Boden and Jimmy are at odds. Kidd deals with her unstable ex. Dawson continues her quest to foster Louie. Casey's new political consultant urges him to think big. The team responds to a dangerous structure fire.
