Firehouse 51 welcomes back some familiar faces and says goodbye to Brett. Violet scrambles to decorate Brett's wedding venue. A call at the expo center takes a shocking turn.
After witnessing a domestic dispute, Brett and Violet decide to take the investigation into their own hands. Mouch vets Truck 81's new firefighter. Herrmann relies on something new to aid him on the job.
Severide hides his serious shoulder injury as he tries to rescue a construction worker from a collapsed building; two teens are trapped in a vehicle.
The squad must help defuse a volatile situation at the jail; Shay continues to be hopeful about motherhood; Herrmann's wife goes into labor; Mills and Dawson face important decisions.
Truck and Squad clash after a tense call rescuing a doomsday prepper. Herrmann struggles with Cindy’s diagnosis. Violet gives Brett and Gallo dating advice.