Anthony Ferraris

Following the subway tunnel collapse, Ruzek and Kidd treat injured passengers and track down the missing offender. Archer and Frost perform a life-saving amputation. Lenox feels the weight of the CPD's hopes as she fights to save one of their own.

Kidd and Severide's honeymoon is interrupted by a dangerous person from their past. Kidd's former academy classmate joins Firehouse 51. Brett and Violet reflect on their relationships.

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.

Casey and Severide disagree on a call, while Boden starts a diet and Brett's birth mother shares life-altering news. A familiar face has a proposition for Herrmann.

A suburban house fire involving a mother and son hits home for Casey and Gallo. Meanwhile, Kidd has a charitable idea to help give back to her community.

After responding to a fire at a property belonging to a drug cartel, Casey suspects Cordova when money is found missing from scene.