A month after Voight's close brush with death, Intelligence is overwhelmed with cases as they catch a high-stakes drug bust.
Atwater struggles to find balance as he teams up with a forensic psychologist on an armed robbery case.
Assistant State's Attorney Chapman assists Intelligence with a sensitive investigation that drudges up painful memories for Voight.
In the midst of a momentous rainstorm, Intelligence lends support to Officer Cook when she and her partner disagree about an investigation.
Burgess is put to the test as she looks to make an advancement in her career.
Torres' previous transgressions haunt him as Cook takes on a tense undercover assignment.
The unit learns the truth about a secret Torres has been keeping, as Deputy Chief Charlie Reid puts a focus on Intelligence.
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.
Burgess fights for her life as the team scrambles to find her kidnapper; Dep. Supt. Sam Miller is desperate to find her son's killer; Voight and Upton deal with the aftermath of their 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.
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 death 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.
When Atwater disappears at the house of a convicted felon, the intelligence unit rallies to rescue him before it's too late.
The team works with a visiting detective to put an end to a gang's brutal tactics; Antonio learns that the detective has a hidden motive for being in Chicago; Voight learns that the body of his son's killer has been found.
A basketball star is found murdered after an anti-police rally; a politically charged environment must be navigated while tracking down the killer; complicating matters further, Woods' daughter Brianna is tangled up in the case.
Intelligence tracks down a vigilante who is killing rapists; Burgess begins to question if the men who attacked her sister truly paid for their actions.
A string of bombings is targeting members of the media; the team enlists firehouse 51 to help examine the devices and prevent the next attack.
When a prominent alderman who is known for his urban revitalization efforts is killed, Intelligence looks into the corruption haunting his neighborhood; Olinsky feels pressure after receiving an ultimatum from Woods.
Upton brings back an old undercover identity to help take down a meth ring spearheaded by a former contact; with pressure from Woods mounting, Voight calls in a favor for Olinksy.
A string of robberies leads back to an unlikely individual; Voight confronts a key witness in the Bingham investigation.
Voight witnesses the kidnapping of a young woman with a mysterious connection to his past; intelligence works to find a connection between her kidnapping and several bank robberies; Olinsky gets one step closer to standing trial for Bingham's murder.
Halstead and Atwater go under cover to prevent military-grade weapons from hitting the street; Voight calls in a favor to clear Olinsky's name for Bingham's murder.
Tensions run high as Intelligence seeks justice for Olinsky after he's stabbed in prison; Antonio's loyalty is put to the test; Woods looks to take down Voight once and for all.