A new face at Firehouse 51 causes tension, while rising chaos in the city brings new challenges to the team. Herrmann stalls on plans of relinquishing his office to Mouch.

Vasquez fights to prove himself at 51. Violet and Novak pursue a troubling mystery. Herrmann is on a quest to keep Molly's profitable.

When city budget cuts stretch crews thin, Pascal takes matters into his own hands. Vasquez looks to an old friend for help. An incident in the field hits close to home for Violet.

Firehouse 51 must band together after a devastating fire catches them off guard. Vasquez continues his quest for answers. Violet and Novak face an unexpected roadblock in the new training protocol.