When a gang of suspected murderers begins targeting a new victim each night, the BAU travels to Portland to head them off before they can strike again.
Before moving to Madrid, Severide meets an experimental surgeon and reunites with his estranged father. Meanwhile, Boden tries to save a kid from a life of crime.
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.
Detective Voight plays with fire to get Lieutenant Casey to retract his statement and paramedic Dawson's career is close to flatlining.
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.