Kidd and Severide investigate a trucking company responsible for a string of accidents. Herrmann recruits Kylie to help get new radios. Firehouse 51 celebrates Violet's birthday. Carver's allegiances are torn.

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.

Severide and Van Meter investigate a fire at a family-owned restaurant. Pascal questions Kidd's leadership.

After Damon disobeys Kidd's orders on a call, he turns to Severide to protect him. Herrmann searches for the perfect scent to spice things up with Cindy.

A new chief shakes things up at Firehouse 51; Violet and Novak work to uncover the truth behind a car crash; Cruz keeps a watchful eye on Severide and Damon's growing bond.

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.

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. Cruz and Chloe's marriage problems come to a head.

Severide goes for an unexpected ride on Truck 81. Ritter's worlds collide when his secret cop boyfriend helps 51 track down Severide and the missing rig.

Severide steps in as ranking officer at 51. Kidd fights to save her Girls on Fire program. Cruz's family is threatened when someone from Javi's past resurfaces.

Severide, Kidd and Van Meter investigate a fire at a recording studio. Kylie helps James keep a secret from Boden. Mouch struggles to maintain boundaries with a paramedicine client.

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.

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.

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 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.

Julia spends a couple of days at 51. Boden's stepson, James, returns desperate for Boden to help his mother. After a little girl starts a fire in her backyard, Kidd and her team decide to dig deeper.

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.

Mouch sets out to change his legacy and nickname. Ritter pushes Herrmann to see a doctor. Brett searches for the perfect wedding venue.