Atwater (LaRoyce Hawkins) is settling into his new gig on intelligence as Antonio (Jon Seda) is relegated to desk duty while recovering. Lindsay (Sophia Bush) finally realizes she has no way out and confides in Voight (Jason Beghe) for help. Meanwhile Jin (Archie Kao) is confronted about his secret meetings with Stillwell (guest star Ian Bohen).
As the Sheldon Jin murder investigation moves forward, Voight (Jason Beghe) 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 (Patrick Flueger). At District, Burgess (Marina Squerciati) meets her new partner, Sean Roman (Brian Geraghty) and tension is high from the start.
Commander Perry (guest star Robert Ray Wisdom) notifies the Intelligence unit that Pulpo (guest star Arturo Del Puerto) has been released to help track down a dangerous cartel leader. This doesn’t sit well with our team as he kidnapped one of their own and no love is lost between sides. Meanwhile, Ruzek (Patrick John Flueger) gets some difficult news as a blast from Lindsay’s (Sophia Bush) past comes back, giving us a glimpse at where she came from.
As Antonio’s life is now in question, Voight and Platt (guest star Amy Morton) open up about their pasts. Jin is caught while tinkering with Voight’s computer and uses the only scapegoat possible to keep him in the clear. At the same time with Charlie (guest star Billy Wirth) back in town Lindsay realizes she’s going to have to come clean about a few things.
Voight and the team discover a massacre, eight million in cash stolen and two wounded men in a clearing house. During questioning, one guy, Perko (guest star Dusan Faeger), provides some intel that is key to the case and leads Antonio to realize that two gangs were involved. Burgess steps up to help the unit and prove herself to Voight.
The Intelligence Unit works to find the bombers. Even with government agencies in the mix, Voight and his team work the case from their own angles and connections. Lindsay and Antonio question doctors who handled the transplant surgery for an Ambassador from Syria, but no clues emerge. Olinsky gets some solid intel and the team work from there. It’s a race against time as they realize there may be additional bombs targeted to detonate.
In responding to a call Atwater (LaRoyce Hawkins) and Burgess (Marina Squerciati) discover a gunshot victim and the only witness is Lexi Olinsky (guest star Alina Taber). The shooting is tied to a Latin gang. To protect Olinsky’s (Elias Koteas) daughter, Voight (Jason Beghe) takes the case from the Gang Unit.
Voight pulls Halstead’s badge when Lonnie Rodiger is found dead. After a car accident Severide (guest star Taylor Kinney) and Clarke (guest start Peter Mills) discover the torso of Dr. Elliot who has been instrumental in putting away high profile criminals. With Intelligence down one Sumner (guest star Sydney Tamiia Poitier) is given an opportunity to prove herself.
The Fitori murder case is brought to the intelligence unit and Voight’s (Jason Beghe) son, Justin (guest star Josh Segarra), may be involved. Gradishar (guest star Robin Weigert) fills Antonio (Jon Seda) in on the arrangement between Internal Affairs and Voight which increases friction between Voight and Antonio. Back at the precinct Ruzek (Patrick Flueger) helps Burgess (Marina Squerciati) get back at desk sergeant Platt (guest star Amy Morton).
Voight (Jason Beghe) is assigned a new Internal Affairs handler, Stillwell (guest star Ian Bohen) who proves to be suspicious of Voight’s actions. During an investigation involving a gambling ring Voight is forced to work with his former partner from the Gang Unit, Shi (guest star Mark Dacascos). At the same time Halsted (Jesse Lee Soffer) remains fixated on Lonnie Rodiger (guest star Matthew Sherbach) and enlists Jin’s (Archie Kao) help to gather more information.
Atwater (LaRoyce Hawkins) and Burgess (Marina Squerciati) are given a new patrol car, but are challenged with keeping it brand new. A run in with a psychotic woman leads the Intelligence Unit to discover a drug smuggling operation which has put several girl’s lives in peril. Voight’s (Jason Beghe) overprotective act with Lindsay (Sophia Bush) leads her right where he doesn’t want as she also helps to keep Justin out of trouble.
Voight (Jason Beghe) and Antonio (Jon Seda) enlist the help of agents at the Special Victims Unit in New York, Fin (guest star Ice T) and Rollins (guest star Kelli Giddish), to help track down the culprit of a series of rape/murders. Burgess (Marina Squerciati) has an opportunity to prove herself to Intelligence. Elsewhere Lindsay (Sophia Bush) enlists the help of Halstead (Jesse Lee Sopher) to act as her date for her high school reunion to get back at an old rival.
Voight (Jason Beghe) and team head to a house that’s been associated with a number of top gangs. Events at the search result in Ruzek (Patrick Flueger), being encouraged to seek some counseling which may have lasting repercussions professionally and personally. Meanwhile Halstead’s (Jesse Lee Soffer) temper rises when he comes in contact with some unwelcomed people from his past.
More is learned about Halstead’s (Jesse Lee Soffer) dislike of the Rodiger family and it’s family relationships all around as Olinsky (Elias Koteas) shows a paternal side with his daughter Lexi (guest star Alina Taber) in an attempt to protect her and as Voight’s (Jason Beghe) trying to help his son who has recently been released from jail. Meanwhile the Intelligence Unit investigates a counterfeiting operation after discovering some high end cloth-like paper.
In the series premiere, after a slew of brutal slayings, District 21, led by Sergeant Hank Voight (Jason Beghe) go after a Columbian drug cartel cleaning house in Chicago. They discover D’Anthony (guest star Isaac White) who proves to be an asset in the investigation. At District, complicated histories and unit rivalries surface which could end up costing them one of their own. Meanwhile, Rookie Kyle Ruzek (Patrick Flueger) is pulled from the police academy by Olinski (Elias Koteas) to join the team.
Antonio’s (Jon Seda) son was kidnapped and he has a feeling the Columbian drug gang is to blame. Pulpo (guest star Arturo Del Puerto), the Columbian gang leader, is being held in jail and suggests his release may trigger the release of Diego (guest star Zach Garcia). During the investigation, Halstead (Jesse Lee Soffer) learns some new information about Lindsay (Sophia Bush).
Halstead (Jesse Lee Soffer) and Atwater (LaRoyce Hawkins) go undercover to prevent military-grade weapons from hitting the street. Meanwhile, Voight (Jason Beghe) calls in a favor as a last-ditch effort to clear Olinsky’s (Elias Koteas) name for Bingham’s murder.
Tensions run high as Intelligence seeks justice for Olinsky (Elias Koteas) after he's stabbed in prison. Antonio’s (Jon Seda) loyalty is put to the test and Woods (guest star Mykelti Williamson) looks to take down Voight (Jason Beghe) once and for all.