An armed robbery case quickly turns into a homicide investigation. When a suspect's background suggests domestic violence, Upton is forced to reckon with her childhood. Voight and Halstead butt heads.

Before The Fall. Voight enlists the help of a reformed gang member to get a key witness' testimony in a murder case. More lives are put on the line as a gang war brews.

Lines. Intelligence does everything they can to build a case against the elusive leader of a drug ring, but things get complicated when Rojas realizes someone she cares about might be involved.

Buried Secrets. The clock is on after Ruzek witnesses a woman's kidnapping and the team races to put the pieces together. Burgess tries to connect with Ruzek but he mysteriously distances himself from her.

Silence Of The Night. Atwater goes undercover to take down a gun trafficking ring, but discovers an officer from his past is undercover in the same organization.

The team responds to the shooting of a girl and must work while facing the increased attention on police reform. Atwater is targeted by officers who want to hurt him for standing against the blue wall.

The son of a former cop is involved in a murder and Moore pressures Voight to charge him quickly. Voight wants to help Atwater end this mistreatment but they can't agree on the right way to handle it.

Ruzek and Burgess discover a child walking alone, 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. Dep. Supt. Samantha Miller is hesitant to defend him until she knows the whole story.

The team investigates a rash of car-jackings and finds that the truth is more complicated than they realize. Burgess makes a discovery about a previous case that will change her life forever.

Halstead and Ruzek try to infiltrate a crime ring and encounter a complicated situation. The team recruits an unlikely ally to help solve a murder.