Jeff Lima

A spate of robberies comes to light after a firehouse lockbox key goes missing, and Sgt Hank Voight suspects a firefighter may be involved. With Boden's support, he recruits Cruz to go undercover to help sniff out any suspicious activity.

Casey gets off on the wrong foot with Chief Boden's stand-in, while Mouch flies in Cruz's brother as a birthday surprise.

The shooting of a child in their neighbourhood forces Cruz and his brother to think about the gang, Isabella gets Mills to dress up for a gala, Casey feels sad he will be seeing Dawson less, and Shay gets in deeper with Devon.

Boden tries to keep the firehouse from closing, the romance between Dawson and Casey grows, Cruz worries about his brother's safety, and Severide and Katie make up for lost time.

Tension builds when a group of rabble-rousers attempts to lock down the firehouse. Brett is faced with a monumental decision and Cruz readies himself for a big day. Gallo and Ritter attempt to launch Firehouse 51 into the social media age.

The Firehouse 51 crew has a Thanksgiving to remember when drugs, a car accident, and a gang shooting get in the way of traditional holiday pastimes.