The story of Windy City's Police Department in Chicago.
Cast: Don Kress, Andre Bellos, Jason Beghe, Sophia Bush, Patrick John Flueger, America Olivo, Jon Seda, David Aron Damane, Zach Garcia, Laroyce Hawkins, Heidi Johanningmeier, Christopher Kahler, Kurt Naebig, Emily Peterson, Joe Reegan, Matthew Sherbach, Isaac White
Voight comes up against a younger, more violent version of himself while trying to extract Commander Perry's nephew from a unit of corrupt officers.
When multiple people are shot inside an athletic club intelligence works to find and take down the shooters before there are any more victims. When they discover that all the targets were from the same law firm it's apparent that it is a case of corporate revenge. Now they need to find out what the motive was for these killings. Atwater is dealing with his new assignment, while doing so he plays a key role in locating the shooters. Meanwhile Platt and Halstead are trying to approach Lindsay to see how she's coping with a recent death.
As District 21 is struggling to come to terms with the loss of one of the team they are forced to put their personal feelings aside when a café is bombed. The unit has several suspects and only one good eye-witness, who happens to be a minor. Halstead pulls some strings to convince the mom to let him question Isabella on what she saw. Atwater finds himself in hot water when he makes a crucial mistake. Thanks to the tech savvy Mouse the team is able to gain important intel that could help solve the case. Meanwhile Voight helps Platt when she comes up against several roadblocks in an attempt to get a memorial stone for their fallen member.
Benson is in Chicago helping Intelligence with a rape/murder case similar to a case in New York from a decade ago, so she calls in Fin and Amaro for assistance.
The search is on for one of Chicago's most wanted fugitives after several dead teenage girls are found in a Chinatown factory. When the father of one of the dead girls explains that he paid Dennis Lee to have her brought to America, this hits home with Olinsky. Lee is one of the Chicago's most wanted fugitives and escaped Olinsky once before. Intelligence isn't about to let Lee dupe them again and Olinsky's past files prove valuable in finding Lee's whereabouts. Meanwhile, Sean Roman has an altercation with a fellow officer which lands him in a bit of trouble. At the same time Platt helps prepare Nadia to take her polygraph test after passing the CPD written exam.
Intelligence responds to a drug robbery gone wrong and in their investigation it's revealed that the first person Voight ever gave his card to is linked to a double murder. Voight will fight to keep her family safe. At the same time, we learn the real reason why Halstead's brother Will came to Chicago. Meanwhile Desk Sgt. Platt takes care of a young girl at district.
The death of a protester at a world trade event seems to point to an Argentine official. Halstead's brother arrives in town and is soon stirring up trouble.
Commander Fischer updates Voight on a missing officer that Narcotics had deep undercover with a robbery crew. Antonio connected with one of the crew members years ago, so he's asked to reestablish contact to help them find the officer. Meanwhile, Roman and Burgess are dealing with a squatter situation and they enlist Chicago Fire's Mouch to help.
After they are kidnapped while tackling a dangerous smuggling operation, Roman and Burgess pursue a man without calling for backup. Intelligence are spending the day receiving taser certification.
Bunny comes to Lindsay concerned about a suspicious repeat customer at her husband's rental company. This lead brings Intelligence into a case which robbery-homicide has been working for months. Detective Gina Gawronski downloads their intel to the team, she also happens to be Antonio's former co-worker from Vice. Voight doesn't trust Bunny's motives for the tip.
Antonio and his sister talk to Elliot Gish about the person they think is responsible for the fire that killed Shay; Lindsay has second thoughts about the task force; Platt's new, sunny demeanor results in curiosity.
Complicated clues surround the murder of a mother and her daughter. While, Lindsay prepares for an undercover investigation in Bolivia, and it dawns on Burgess and Roman that they need to put the past behind them.
One of the team goes it alone.
With Burgess in the hospital after suffering gunshot wounds, the intelligence team is determined to find the people responsible. Lindsay delays her start so she can help with this case. Search of the house provides a lead and when a bomb is triggered a key suspect is found. Meanwhile the team takes turns watching over Burgess. Voight informs Burgess of a new opportunity that this affords her.
A huge heroin bust leaves Olinsky's family in danger. Lindsay ends up making a life changing decision about her career.
While Antonio continues his off-duty security job for Asher and Layla, Asher is killed. Voight and Olinsky make sure Antonio is covered. While they work the case Halstead and Lindsay go undercover in a rather uncomfortable location. Kot shows up to ask Lindsay for an answer.
The Chicago Intelligence Unit continues working with Special Victims Unit to take down a child pornography ring.
The murder of a 10 year old witness sends Atwater and Ruzek undercover as inmates in a federal prison.
While trying to help out Olive, Voight is attacked and taken. When he doesn’t show for work the team gets suspicious and begin investigating. Ruzek and Atwater prove they do belong on the team when they demonstrate smarts and savvy tracking down a lead that will hopefully bring them to Voight. Meanwhile Burgess and Roman are trying to track down a girl who has run off with a police badge.
Two teenage girls have gone missing and the team know the clock is ticking to find them. Halstead, Antonio and Lindsay investigate a tenement which gives them a much needed lead. Voight brings the father of one of the girls to district in order to get some honest answers. Meanwhile, Platt puts Roman and Burgess on gun buy-back duty where they ask questions when they aren’t supposed to.
The bounty on Halstead's head becomes a serious reality as an innocent bartender takes a bullet meant for him. Olinsky tries to reason with Bembenek to call off the hit, to no avail. Voight and the team keep this investigation in-house to find the hired assassin. Meanwhile, after a tense interaction at district Platt and Nadia come to an understanding.
Intelligence begins to look into a string of murders where the victims have a dollar bill pinned to their chests. Thanks to some digging by Ruzek, Voight learns his friend was involved in some shady business dealings. Antonio and Halstead follow-up on some leads that help focus in on the culprit and motives for the murders. Meanwhile, Burgess and Roman investigate a series of house break-ins and get some help from Desk Sgt. Platt.
As the Sheldon Jin murder investigation moves forward, Voight is under close watch by Internal Affairs but he's still in complete command of the intelligence unit. A routine undercover job becomes anything but when Voight's SUV is T-boned while trailing an armored car carrying Ruzek. At District, Burgess meets her new partner, Sean Roman and tension is high from the start. Soon she realizes there's more to his story. After a long day, Lindsay pays a visit to someone she hasn't seen in a very long time - her mom, Bunny.