Anthony Ferraris

When a fire ruins a neighbourhood wedding, the Firehouse becomes the replacement venue. Dawson has difficulty returning to life on the job, and tensions run high between Chili and Borrelli.

Firehouse 51 responds to a dangerous structure fire that leaves one of their own in jeopardy. Borelli confronts Boden about his brother's death.

Severide wants to implicate the serial arsonist, Dawson and Shay face the unexpected on a routine call, suspicions indicate Clarke is the mole, and Mouch campaigns for union president.

Cruz comes under investigation when Firehouse 51 and Truck 66 collide, placing Molina in a critical condition.

New-to-the-crew Sylvie shines as the crew answer three dramatic call-outs. Casey asks Newhouse to help dig up dirt on his sister's husband.

Firehouse 51 is thrown into chaos due to a series of mysterious gas leaks. Meanwhile, Brett struggles with feelings about her birth mother. Severide misunderstands his role as Cruz's best man and Mouch bites off more than he can chew.