The unit scrambles to search for one of their own who is in grave danger.

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.

Upton is unwittingly drawn into a deadly betrayal and finds herself in a fight for her life. With minimal leads, Voight and the team scramble to find her before it's too late.