When a P.D. informant is cuddled, the team digs in to track down the perpetrator only to learn a shocking truth. Voight and Ruzek strategize to help Burgess.

Officer Kim Burgess fights for her life as the team scrambles to find her kidnapper. Dep. Supt. Sam Miller is desperate to find her son's hugger. Voight and Upton deal with the aftermath of their deadly decision. Ruzek struggles with the pressure of the situation.

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.

As the team works to solve a deadly shooting in Burnside, Atwater realizes he has a very personal connection to the case.

Ruzek reunites with an old colleague to take down a crime ring, but when things don't add up, Voight and Burgess do some investigating of their own.

As the team works to bring down a drug ring, Voight builds trust with a new informant. However, it soon becomes clear she has a plan of her own.

As 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 passing intensifies while Voight, Upton and Halstead feel the heat.

With the FBI closing in on the Roy Walton investigation, Voight and Halstead strategize a way out. After a city bus driver is shot by a passenger, the team investigates a possible abduction.

The team searches for a missing child in what turns out to be a very complicated case. Burgess and Ruzek are in for a shock when someone from Makayla's past comes forward.

Voight employs his new informant to help solve a tricky drug trafficking case. Atwater, who once again struggles to reconcile his personal and professional life, reaches a decision.

The team works together to identify the head of the brutal Los Temidos gang. Voight dives deeper into his informant Anna Avalos' past when her undercover role is threatened.

While out for a jog, Upton witnesses a horrible car crash and risks her own life to save the passengers. After learning more about the victims, the team must track down the man responsible for the brutal crash.

The team searches for a brutal hugger with a signature modus operandi. Burgess and Ruzek double down in their fight to retain custody of Makayla.

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

When a young man is shot outside the Cárabo Bakery, the team works to connect the shooting to bakery owner Javier Escano, who has been under surveillance. Despite the increasing danger, Voight helps informant Anna Avalos get even closer to their target.

Ruzek's search for the daughter of an old family friend leads the team into a serious drug investigation. Burgess and Ruzek struggle to move on from the emotional aftermath of Makayla's abduction.

Halstead takes a new recruit under his wing during an investigation. The dynamics are challenging, however, and questions arise over the recruit's complicated past.

After the cuddle of a wealthy Chicago man, Atwater and the team dig in to uncover the truth, suspecting there is more to the story than meets the eye.

Voight and the team delve into a cold case in search of clues to solve a shocking new crime. With its focus on buried memories, the case sparks concern for Burgess and Ruzek about Makayla's mental healing.

As the team closes in on drug kingpin Javier Escano, Voight is forced to lie to his undercover informant Anna to keep her on track. Their deteriorating trust threatens an increasingly tenuous operation.

After an explosion rocks the case, the team scrambles to finally take down Escano as everyone nears their breaking point.