Barely Gone. Firehouse 51 is forced to share space with Firehouse 17. An arson case tests Kidd and Severide's relationship. Firehouse 51 says goodbye to one of its own.

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

Trapped. After witnessing a domestic dispute, Brett and Violet take things into their own hands. Mouch vets a new firefighter. Herrmann relies on a new aid on the job.

The Little Things. Julia spends a few days at 51. Boden's stepson is desperate for help for his mother. After a little girl starts a fire, Kidd and her team decide to dig deeper.

On The Hook. Brett and Violet's defibrillator malfunctions on a call. Herrmann tries to find the perfect home for his new recliner. A secret from Gibson's past comes out.

Port In The Storm. Some familiar faces return to Firehouse 51, and Brett says goodbye. Violet scrambles to decorate for Brett's wedding. A call at the expo center turns shocking.

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

All The Dark. A hazmat call at a dialysis center leads to a shocking discovery. Boden clashes with Paramedic Chief Robinson. Carver is concerned about Gibson's behavior.

Something About Her. Severide, Kidd and Van Meter investigate a fire at a recording studio. Kylie helps James keep a secret from Boden. Mouch tries to keep boundaries with a client.

The Wrong Guy. 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.

Inside Man. 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.

Under Pressure. Severide and Violet risk clashing with Chief Robinson after Lennox makes a dangerous decision on a call. Cruz and Chloe's marriage problems come to a head.

Never Say Goodbye. Boden makes a decision that impacts the Deputy Commissioner race. A call triggers painful memories for Carver and Damon. Mouch tries to adjust to the new Truck.