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 under cover 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 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.

Severide is made an enticing offer by a woman he saved from a car crash and the crew bid farewell to a colleague after a blaze at a garage.

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

The crew of Firehouse 51 are full of festive cheer until Casey is accused of stealing a diamond necklace. Meanwhile, sparks fly between Shay and Severide.