Still reeling from the death of informant Anna, Voight faces a new threat as he tries to keep the neighbourhood clean; new wrinkles develop in the Upton, Halstead and Voight dynamic; the team gets a new chief.
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.
A shocking murder pulls rookie officer Dante Torres into his own neighbourhood; as Voight and Atwater help him navigate the case and manage tricky personal dynamics with wary neighbours, Torres realises his life may be forever changed.
Upton's dogged pursuit of a missing teenage girl leads the team into a dark web of human trafficking; chief O'Neal becomes involved with the unit's investigation when it becomes evident his son, Sean, has a connection to the missing girl.
Atwater's reactions during a tense arrest are called into question; the team must dig in to uncover key evidence that could aid in the ongoing investigation and clear Atwater's name.
Jason Beghe
Sergeant Hank Voight
Patrick Flueger
Officer Adam Ruzek
LaRoyce Hawkins
Detective Kevin Atwater
Elias Koteas
Detective Alvin Olinsky
Jon Seda
Detective Antonio Dawson