Andy Ahrens

When Intelligence follows up on a tip Antonio (Jon Seda) and Halstead (Jesse Lee Soffer) received from a reliable informant about an upcoming drug trade, the team is shocked to discover the mutilated body of a man. Upon further investigation, the body is identified as a government official and when Olinksy (Elias Koteas), Ruzek (Patrick Flueger), Lindsay (Sophia Bush) and Halstead question the man's acquaintances they discover he had access to very important devices. Meanwhile, Burgess (Marina Squerciati) helps plan a surprise for Platt (Amy Morton).

Lt. Casey (Jesse Spencer), who is at the center of an undercover operation to bring down a trafficking ring run out of Nesbitt's (guest star Eric Mabius) strip club, finds himself in very dangerous territory. Meanwhile, as a result of the high turnover rate on squad, Severide (Taylor Kinney) gets a rude awakening when Capt. Dallas Patterson (guest star Brian White) is brought in, much to Boden's (Eamonn Walker) dismay. Dawson (Monica Raymund) confirms her suspicions that her life is about to change forever and Jimmy Borrelli (guest star Steven R. McQueen), the new candidate, makes an unusual first impression. Elsewhere, citizens of Chicago band together to take charge of their neighborhood in protest of a drug den in their area, resulting in ramifications that severely hinder members of Firehouse 51, who are called to the scene to battle a blazing fire.

The pressure on Firehouse 51 is at an all-time high as the internal affairs investigation into the handling of a recent fire picks up steam. Just when it appears that game-changing evidence comes to light that would serve to bail out Chief Boden (Eamonn Walker), new twists emerge that put his head right back on the chopping block. Brett (Kara Killmer) and Chili (Dora Madison) respond to a routine call and quickly find themselves in a life and death situation to help aid a stabbing victim who is bleeding out. Meanwhile, a stuck elevator summons the house to a high-rise hotel that tests everyone's mettle and candidate Jimmy Borrelli (guest star Steven R. McQueen) is conflicted when his older brother Danny (guest star Andy Ahrens) looks to get him transferred to a different house. Jesse Spencer, Taylor Kinney, Monica Raymund, David Eigenberg, Yuri Sardarov, Joe Minoso and Christian Stolte also star. Nick Gehlfuss, Oliver Platt, Brian Geraghty, Brian White, Rachel Nichols and Fredric Lehne also guest star.

Lt. Boden (Eamonn Walker) and Jimmy (Steven R. McQueen) find themselves at odds in dealing with the aftermath of recent events while Kidd (guest star Miranda Rae Mayo) is forced to deal with her unstable and volatile ex, Grant (guest star Guy Burnet). With the help of firehouse 51, Dawson (Monica Raymund) tries to put her best foot forward in her pursuit for fostering Louie. At the urging of Susan Weller (guest star Lauren Stamile), his new political consultant, Casey (Jesse Spencer) tends to his Alderman duties and leaves town with her to attend a three-day summit. Much to his surprise, Casey embraces his new role while Susan urges him to consider grander aspirations. Meanwhile, the house responds to a dangerous structure fire that puts one of their own in a desperate situation.

A building collapses and leaves dozens of people trapped and injured; Chief Boden faces a life-or-death decision in the rescue plan; Dawson continues her quest to foster Louie; tensions flare between Casey and Antonio.