S4·E9 Don't Bury This Case (II)
Aired January 3, 2017
Synopsis
Severide is brought into the District for questioning after his car is found to have caused a deadly crash. As the investigation gets underway, the team works to uncover a group of car-jackers who may be the key to Severide's innocence.
The crossover starts on Chicago Fire S05E09 Some Make It, Some Don't (I).