Retired Commander Perry enlists Voight and the team to help extract his cop nephew from a unit of corrupt officers who are robbing drug dealers. When things go bad Voight must take down a younger, more violent version of himself. Meanwhile, Lindsay struggles to stay clean. At the same time a woman from Olinsky's past reaches out to him.

A bust to bring down a heroin kingpin goes horribly awry. Olinsky reveals a dark secret from his past, and Halstead tries to get through to a spiraling Lindsay.

A child abduction case hits too close to home for Dawson. Lindsay and Bunny's relationship reaches a critical impasse and Roman reveals his secret to Burgess.

The team is terrorized by a gun-wielding father who is desperate to find his missing daughter. Bunny stirs up accusations of misconduct from Voight's past.

Voight seeks revenge on the man who tried to kill him. A rumor causes a rift in Intelligence.

Ruzek's job is on the line after an ill-fated undercover op.