After their defibrillator malfunctions on a call, Brett and Violet search for answers. Herrmann tries to find the perfect home for his new recliner. A secret from Gibson's past comes to light.

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.

Violet clashes with her new partner. Severide discovers a hidden stash of money on a call and squares off against the cops working the case. Mouch gets a parking ticket.

A hazmat call at a dialysis center leads to a shocking discovery. Boden clashes with Paramedic Chief Robinson. Carver notices a concerning change in Gibson's behavior.

Severide and Violet risk clashing with Paramedic Chief Robinson after Lennox makes a dangerous decision on a call. Capp and Tony attempt to break a world record.

Boden makes a decision that impacts the race for deputy commissioner. A tense call brings up painful memories for Carver and Damon. Mouch struggles to adjust to the new truck.

Violet risks her job to deliver a baby on a tragic call. Mouch, Capp and Tony help Cruz track down Javi's stolen bike. Damon's departure weighs on Severide.