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.
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.
Harper puts Aaron through Plain Clothes Day; two witnesses for an upcoming grand jury case are murdered.
Thorsen reluctantly goes on a reality show to help rebrand his image; the show's producer is found murdered and the team must investigate.
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.