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