Detective Holloway continues to entrust Lt. Severide to watch over her young son at the firehouse while she testifies in court as part of an undercover operation. When the situation takes an unexpected turn, Severide is left to deal with the aftermath. The firehouse responds to a blaze at an art gallery that has a victim trapped inside and prompts Cruz to make a rash decision amid the chaos. Casey receives a suspicious package in the mail that casts suspicion on him from the Board of Ethics. Meanwhile, Brett discovers Otis isn't taking care of his own important issues and confronts him, but finds he is stubborn and more interested in rallying the troops to organize a trip to Las Vegas for the annual firefighting conference.
No job is more stressful, dangerous or exhilarating than those of the Firefighters, Rescue Squad and Paramedics of Chicago Firehouse 51. These are the courageous men and women who forge headfirst into danger when everyone else is running the other way. But the enormous responsibilities of the job also take a personal toll.
With big reputations and hefty egos, the pressure to perform and make split-second decisions is bound to put squad members at odds. When a tragedy claims one of their own, there's plenty of guilt and blame to go around. In the middle of a divorce, Lt. Matthew Casey tries to go about business as usual, but can't help butting heads with the brash Lt. Kelly Severide of the Rescue Squad - and each blames the other for their fallen team member. When it's "go-time", though, they put their differences aside and put everything on the line for each other. This is a look inside one of America's noblest professions.