Ruzek and Burgess discover a child walking alone in the middle of the street, and when they take her home, they discover that her entire family has been murdered; Upton is approached with a job offer from the FBI.
A cop is murdered, and suspicion falls on someone who has been holding a grudge against the officer. Intelligence works to solve the case, but Deputy Superintendent Samantha Miller's hesitant to defend him until she knows the whole story.
After a seemingly innocent young man is gunned down in the street, the team works to bring the suspected culprit, but the case is more complex than it appears, the grief stricken father is determined to do his own undercover work.
The team goes under cover to bring down dangerous new drug dealers who are eliminating the competition. Ruzek's CI is a loose cannon and threatens the whole operation.
Ruzek and Atwater are tasked with arresting a fellow officer after a shooting. The situation turns dangerous when it's clear someone wants to assassinate the officer.
When a local business owner is gunned down in his shop, it becomes personal for Atwater, who patrolled the neighborhood as a young cop. Dep. Supt. Samantha Miller comes to Voight with a special request about Andre Cooper.
A wellness check on a family reveals signs of foul play and Upton is determined to find the parents and young daughter. As she delves further into the troubled family dynamics, she finds herself reflecting on her own childhood trauma.
The shocking murder of a young pregnant woman leads the team on a desperate hunt for the killer, revealing something even darker than expected. Burgess has to make a tough decision about Makayla.
Voight and the team pursue a ruthless crime ring whose business has hit close to home. As they dig deeper, the extent of the danger becomes more apparent. Deputy Superintendent Samantha Miller second-guesses her decisions.
Burgess fights for her life. Dep. Supt. Sam Miller is desperate to find her son's killer. Voight and Upton deal with the aftermath of their deadly decision. Ruzek struggles with the pressure of the situation.
When a P.D. informant is murdered, the team digs in to track down the perpetrator only to learn a shocking truth. Voight and Ruzek strategize to help Burgess.
Halstead's past resurfaces when a former Army colleague is implicated in a deadly blast. As the FBI launches an investigation into Roy's disappearance, Upton feels the pressure of the secret she and Voight are sharing.
When Upton and Ruzek answer an emergency call to an abandoned house, their investigation leads them down a dark path. Upton feels the pressure of the secret she and Voight are sharing.
The team investigates the stabbing of a father with two young daughters; they begin to suspect there is more to the story than meets the eye. The FBI investigation into Roy Walton's death intensifies.
With the FBI closing in on the Roy Walton investigation, Voight and Halstead strategize on a way out. After a city bus driver is shot by a passenger, the team investigates a possible abduction.