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.
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.
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.
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.
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).
After a series of brutal home invasion robberies, Upton immerses herself in the case and finds herself caught between Voight and Halstead.
Voight and the team pursue a ruthless crime ring whose business has hit close to home. As they dig deeper, they extent of the danger becomes more apparent. Deputy Superintendent Samantha Miller second-guesses her decisions.
A wellness check on a family reveals signs of foul play and Detective Hailey is determined to find the parents and young daughter. As Upton delves further into the troubled family dynamics, she finds herself reflecting on her own childhood trauma.
The team pursue a crafty serial rapist. Sergeant Voight finds himself resisting some old, familiar tendencies in his quest for justice.
Ruzek and Atwater are tasked with making an arrest after a high-profile shooting. The situation becomes complicated when it’s clear someone doesn’t want them to make it back to the station.
When a local business owner is gunned down in his shop, it becomes personal for Atwater who patrolled the neighborhood as a young cop. Deputy Superintendent Samantha Miller comes to Voight with a special request about Andre Cooper.
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 but the truth is more complicated than they realize. The team recruits an unlikely ally to help solve a murder.
The son of an influential former officer is implicated in a murder and Moore pressures Voight to charge him quickly so that the CPD isn’t accused of preferential treatment. The stakes are raised in Atwater’s fight against the blue wall after patrol officers stop responding to his team’s calls. Voight wants to help Atwater end this mistreatment but the two can’t agree on the right way to handle it.
Ruzek and Burgess discover a child walking alone in the middle of the street and when they take her home, they discover her entire family has been murdered. Upton is approached with a job offer from the FBI.
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 outside of work but he mysteriously distances himself from her.
Atwater goes undercover to take down a gun-trafficking ring, but discovers an officer from his past is undercover in the same organization.
An armed robbery case quickly turns into a homicide investigation. When one suspect’s background suggests domestic violence, Upton is forced to reckon with her childhood. Voight and Halstead butt heads over Halstead’s righteous instinct.
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.
After receiving a 911 call about a possible domestic dispute, Burgess follows up with the location of the call with Platt and they find a murder victim. Later on, the Intelligence unit discovers that the killer is wanted by the FBI in six states for creating a sex trafficking ring. Burgess is injured while saving the victim who made the 911 call to her, and she loses the baby.
A homeless man's murder leads Intelligence to a criminal who has evaded capture for years. Rojas has a troubling experience with a young mentally ill man.
As they await news of Halstead’s fate, the team tries to focus on work, turning their attention to an illegal arms dealer. Atwater discovers his brother, Jordan, is back in Chicago and could be tied to the case. Voight faces the tricky task of how to deal with Halstead’s shooter. Burgess finally makes her decision.
Ruzek and Burgess’s secret begins to have severe implications for their police work. A series of deadly acts of vandalism causes tensions to run high in the insular neighborhood of Canaryville. Atwater tries to reach out to his brother, but only pushes him further away.
Voight pulls Darius in after Crawford asks Intelligence to investigate a dangerous drug, but there is little trust in the relationship. When their plan to nail a dealer goes awry and another CI is murdered, the team must make a tough decision about Darius.
After injuring herself while pursuing a suspect, Burgess receives a shocking diagnosis. A homicide case turns into a missing persons case, with a sinister twist. Voight has to decide between justice and the letter of the law.
After zeroing in on the suspect responsible for the bioterrorism that’s gripping Chicago, the PD prepares to undertake their biggest manhunt yet. Upton is torn between helping track down the perp and providing emotional support to the scared young girl that needs her. Voight fears his team is being sent on a wild goose chase.
A murder in a Bulgarian neighborhood results in a challenging investigation when locals won't talk to police.
When Kelton is found murdered, Voight’s grudge against the mayor-elect puts him under suspicion. Upton and Halstead are eager to prove their sergeant’s innocence, but the more evidence they gather, the closer they come to doing the opposite. After making bail, Ruzek searches for a missing Antonio.
When Atwater goes undercover in a dangerous South Side drug syndicate, he learns there may be more to its kingpin than meets the eye. Halstead tries to join Atwater undercover, but finds himself at a disadvantage. Voight petitions the brass to show Ruzek leniency in his court case.
A violent crew is hitting pharmaceutical delivery trucks and stealing drugs, but their motivation is more complicated than just money; the case tests Upton and Ruzek's relationship.
Antonio struggles with his guilty conscience as he tries to take down a major drug dealer; Voight takes a shot at Kelton to protect his team.
A mayoral candidate is shot by an unidentified sniper, and CPD races to catch the shooter before he can take out his next target.
Voight pulls Darius in after Crawford asks Intelligence to investigate a dangerous drug, but there is little trust in the relationship. When their plan to nail a dealer goes awry and another CI is murdered, the team must make a tough decision about Darius.
With the threat of a gang war looming, Voight and Ray Price must organize a peace summit to end the bloodshed before more innocent people get hurt. Meanwhile, Burgess evaluates her future with Blair.
The team travels to a Wisconsin gun show to take down a supplier who’s manufacturing “cop killer” machine guns. Before going undercover together, Burgess (Marina Squerciati) discovers that Upton (Tracy Spiridakos) is dating Ruzek (Patrick John Flueger).
Using information from Chicago Fire's Cruz, Intelligence chases down the robbery crew that’s been using the lockbox key. Voight (Jason Beghe) is under pressure to bring the crew to justice without tarnishing the reputation of a murdered firefighter who might have been involved.
Voight and Ruzek lock horns over how to handle the aftermath of the Antonio situation. Meanwhile, a series of violent carjackings turns deadly, and Ruzek must rely on a C.I. he grew up with to help solve the case.
Intelligence crosses with a mayoral candidate while investigating the fatal shooting of a well-known defense attorney, and Antonio returns to work but questions his own judgment when an operation goes sideways.
Intelligence suspects the leader of a local mosque is behind the bombing of an Army recruitment station. After a second explosion, Voight (Jason Beghe) urges Halstead (Jesse Lee Soffer) to follow the facts and not let his time in the service cloud his judgment.
While CPD tries to take down a drug kingpin, Atwater (LaRoyce Hawkins) faces a tough choice between doing what’s required to solve the murder of a young dealer and what’s best for the community.
A ride along goes sideways, and Burgess (Marina Squerciati) is faced with a difficult choice: follow the advice of Voight (Jason Beghe), or a potential new ally.
While undercover, Ruzek (Patrick John Flueger) discovers his father (guest star Jack Coleman) is working for a suspected drug dealer and is forced to ask the question: is his dad involved?
Bad heroin is causing overdoses in Chicago, and Intelligence is a man down with Voight (Jason Beghe) suspended. Antonio (Jon Seda) takes charge, but Ruzek (Patrick John Flueger) undermines his authority.
After discovering the true cause of the high-rise fire, Intelligence races to find the man responsible. And for Halstead (Jesse Lee Soffer), it's personal.
A string of stash house robberies lead back to an unlikely individual. Voight (Jason Beghe) confronts a key witness in the Bingham investigation.
After Voight (Jason Beghe) 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. Ruzek (Patrick John Flueger) gets a tip that a grand jury has been summoned, putting Olinsky (Elias Koteas) one step closer to standing trial for Bingham’s murder.
Intelligence investigates a string of bombings targeting members of the media. Racing against a ticking clock, the team enlists Firehouse 51 to help examine the devices and prevent the next attack.
When a prominent Alderman known for his urban revitalization efforts is killed, Intelligence looks into the corruption haunting his neighborhood. Meanwhile Olinsky (Elias Koteas) feels pressure after receiving an ultimatum from Woods (guest star Mykelti Williamson).
When Atwater (LaRoyce Hawkins) disappears at the house of a convicted felon, the evidence doesn't look promising - with his belongings and his blood left behind. Intelligence rallies to rescue him before it's too late. And Atwater struggles for survival faced with not only his captor but also a difficult connection to his past.
Antonio (Jon Seda) finds himself getting close to the Salvadoran Detective, Marcella Gomez (guest star Sofia Lama), only to learn she has a hidden motive for being in Chicago. Meanwhile, Voight (Jason Beghe) learns that the body of his son's killer has been found.
The death of Judge Tommy Wells' (guest star John Pankow) daughter puts Intelligence on the track of a pill mill spreading into the suburbs of Chicago and the doctor enabling it. Meanwhile, Voight (Jason Beghe) discovers who's been leaking information from the 21st.
Halstead's (Jesse Lee Soffer) partying with Camila (guest star Anabelle Acosta) unintentionally puts him in the middle of a drug-related homicide. He's forced to choose between loyalty to his unit and his girl. Meanwhile, Voight (Jason Beghe) finally discovers the mole in his unit.
A picture perfect family is shot dead in their home and the team goes in search of a drug dealer with a likely connection. Voight (Jason Beghe) asks for the help of Vice Sergeant Sean McGrady (guest star Wil Traval) who has an old beef with Upton (Tracy Spiridakos). When McGrady turns up dead during the investigation, the case takes an unlikely turn.
In the wake of several gang-related child abductions, Intelligence must race against time to find a kidnapped boy. Owing to their swiftness and military precision, the team scours the VA records and tracks the suspects to a former Army Ranger. With his previous experience as a Ranger, Halstead (Jesse Lee Soffer) convinces Voight (Jason Beghe) to send him undercover to try and get information from inside.
When a young Latina woman is brutally murdered, Intelligence suspects she may have been working as a drug mule. With Antonio (Jon Seda) leading the case, the team's investigation takes them into the grim world of meat processing, and the discovery that there may be a different motive behind her death.
While investigating a drug-related homicide, Intelligence is stonewalled by the 'no-snitch' culture of the neighborhood. And Atwater (LaRoyce Hawkins) discovers a personal connection to the case. Meanwhile, the police's own code of silence is put to the test when Upton (Tracy Spiridakos) is asked about Ruzek's (Patrick John Flueger) rough altercation with a suspect.
A live video is streamed online showcasing a tortured man being beaten and burned alive. Upon further investigation, the victim's identity is traced back to that of a man who had been previously locked up for statutory rape. When another attack of a similar nature occurs, Intelligence finds a connection between the crimes, suspected pedophiles, and group named the Perv Hunters. Meanwhile, Lindsay (Sophia Bush) runs into a few bumps in the road - both personally and professionally.
When Lindsay (Sophia Bush) receives a panicked call from her mother Bunny (guest star Markie Post) whose boyfriend had just been shot, Lindsay must figure out the best way to approach the situation, as her mother is now a murder suspect. The case opens up when a group of high school students OD, and the drugs in question relate back to the situation with Bunny. In addition to her mother's issues, Lindsay finds herself up against the review board dealing with consequences of her actions.
After encouraging her sister to spend a night out with friends, Burgess (Marina Squerciati) wakes to find that Nicole (guest star Jules Willcox) never made it home. As the guilt begins to eat at Burgess, the team in Intelligence bands together to make finding Nicole their main priority. The case kicks into high gear when she is found clinging to life in an El station.
While investigating the murder of a teenage boy, Voight (Jason Beghe) finds a connection with the murder weapon - linking it to a case that he worked on 17 years ago. While the victim's father (guest star Philip Casnoff), a prominent defense attorney, tries to get the case taken over by Area Central Homicide, Voight digs back into the old case under the watchful eye of his former partner, Lieutenant Denny Woods (guest star Mykelti Williamson).
Olinsky's (Elias Koteas) daughter remains in critical condition following a massive fire - leaving Intelligence on edge, but more determined than ever to track down the suspect. Voight (Jason Beghe) opens up the case, knowing that he has Stone (guest star Philip Winchester) and his team's full support in the investigation, and all of Firehouse 51 behind him to examine potential origins of the fire. Intelligence works to connect the dots between the building owner, those who were inside, and a string of potential suspects.
After being tipped off about a woman running barefoot through the woods, Intelligence is led to a kidnapping victim locked up in a shipping container. The bizarre scenario leaves Voight (Jason Beghe) questioning the legitimacy of the case, and sends the team on a twisted trail to get to the bottom of it. Meanwhile, a former relationship of Halstead's (Jesse Lee Soffer) comes back into the picture, much to the surprise of Lindsay (Sophia Bush).
The body of a 15-year-old girl is found crushed in an abandoned building after she runs away from a treatment center for troubled girls. Voight (Jason Beghe) sends Halstead (Jesse Lee Soffer) undercover as a guard to work from the inside at the center, where he believes the girls are trading sexual favors for something in return. Meanwhile, Platt (Amy Morton) feels guilty because the victim was brought into the District last year, and Platt doesn't remember her.
When a charred body is found in a torched house, Intelligence must work to identify the victim, as well as a young boy who is found badly injured inside. As they look to determine the cause and who may have been involved, they are faced with a web of secrets and lies. Meanwhile, Lindsay (Sophia Bush) and Halstead (Jesse Lee Soffer) receive an odd warning about Rixton (guest star Nick Wechsler) that leaves them suspicious.
After the body of young woman is found with multiple gunshot wounds, Intelligence uncovers details of her case that are similar to other deaths. They work to link all of these murders together to pin down the serial killer, and appease the families of the victims who have been looking for answers. Meanwhile, Lindsay (Sophia Bush) decides to meet her biological father (guest star Tony Crane) for the first time, and Voight (Jason Beghe) welcomes Kenny Rixton (guest star Nick Wechsler) to the team when Ruzek (Patrick John Flueger) takes an undercover assignment.
When a mutilated sex offender is found dead, it is unclear if he was the victim of a hate crime, sexual assault or self-mutilation. As Intelligence questions those related to the case, they find themselves up against a private "special police" force who may be covering up illegal activities. Meanwhile, Halstead (Jesse Lee Soffer) runs Jimmy's (guest star Tony Crane) DNA to confirm that he is actually Lindsay's (Sophia Bush) father.
Voight (Jason Beghe) calls the team to investigate a homicide involving the only witness in a rape and murder case against an extremely young man, Oliver Tuxhorn (guest star Gus Halper). Intelligence looks into Tuxhorn's family and their finances as they try to determine if someone was paid to take out the victim. Meanwhile, Stone (guest star Philip Winchester) offers Antonio (Jon Seda) a job as lead investigator for the state attorney's office, and Burgess (Marina Squerciati) and Sorensen's (guest star Kevin Kane) body cameras capture a bizarre exchange with a man that they pull over.
When a young officer is shot dead in the lobby of an apartment building, Intelligence looks to the latest known offenders who have threatened the police. But when a second officer is killed, the team finds that they are dealing with someone who is highly trained and knowledgeable. Voight (Jason Beghe) works to keep the case contained as they deal with Chicago's ever-present war against the police. Meanwhile, Lindsay (Sophia Bush) confronts Antonio (Jon Seda) about his new job with the State's Attorney.
When a car plows through a crowd of concert goers and gunfire erupts, Lindsay (Sophia Bush) and Ruzek (Patrick John Flueger) are on the scene. Unsure of the motive and concerned a terrorist group may be responsible, Voight (Jason Beghe) orders in Homeland security, customs and the F.B.I. to assist. At the same time, Burgess (Marina Squerciati) spots Atwater's (LaRoyce Hawkins) brother, Jordan (guest star Ahmad Nicholas Ferguson), out where he shouldn't be. The team use their connections to throughout the city to bring some peace to the community before more blood is shed.
Intelligence investigates a gruesome case. Upon further examination, it appears the victim was wearing a CPD-issued wire at the time of his death. Meanwhile, Burgess (Marina Squerciati) meets her new partner, Julie Tay (guest star Li Jun Li), who came from one of the worst assignments in the city. Together they respond to their first call, and Tay shares details of her past. Additionally, Commander Crowley (guest star Barbara Eve Harris) confronts Lindsay (Sophia Bush) about why she and Voight (Jason Beghe) were at that location on the night that Intelligence pursued Justin's killer. Also starring Jon Seda, Jesse Lee Soffer, Patrick John Flueger, Elias Koteas, LaRoyce Hawkins and Amy Morton. Guest starring Jesse Spencer, Philip Winchester, Marlyne Barrett and Samuel Hunt.
When a call comes in reporting a car being stripped, Burgess (Marina Squerciati) and Tay (guest star Li Jun Li) respond and discover a badly beaten young man and his fiancé missing. Fearing a public relations nightmare Voight (Jason Beghe) and the team are on their best behavior as they search for answers and the missing woman. At the same time, Lindsay (Sophia Bush) surprises Halsted (Jesse Lee Soffer) with a big question. Commander Fogel (guest star Ian Bedford) berates Platt for going over his head to have Tay assigned to District 21. Also starring Jon Seda, Patrick John Flueger, Elias Koteas, LaRoyce Hawkins and Amy Morton. Guest starring Brian Tee, Samuel Hunt, Barbara Eve Harris and Sam Straley.