When a convicted murderer hijacks a prison van, the team scrambles to find him and the abducted prison guard before it's too late. Burgess questions Ruzek's motives in a case, creating tension between the two.

The team investigates a string of brutal pharmacy robberies, and Halstead connects with one of the victims about their Army careers. Upton suspects there is more to the story and confides in Voight.

As Richard Beck's timeline for a deadly attack moves up and Samantha panics, Ruzek and the team scramble to get ahead of unprecedented disaster.