After a slew of brutal slayings, District 21, led by Sergeant Hank Voight go after a Columbian drug cartel cleaning house in Chicago. They discover D’Anthony 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 is pulled from the police academy by Olinski to join the team.

Antonio’s son was kidnapped and he has a feeling the Columbian drug gang is to blame. Pulpo, the Columbian gang leader, is being held in jail and suggests his release may trigger the release of Diego. During the investigation, Halstead learns some new information about Lindsay. Voight offers Antonio a new approach to get information on Diego’s whereabouts.

Voight and team head to a house that’s been associated with a number of top gangs. Events at the search result in Ruzek, being encouraged to seek some counseling which may have lasting repercussions professionally and personally. Meanwhile Halstead’s temper rises when he comes in contact with some unwelcomed people from his past.

More is learned about Halstead’s dislike of the Rodiger family and it’s family relationships all around as Olinsky shows a paternal side with his daughter Lexi in an attempt to protect her and as Voight’s 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. Sergeant Platt sends Atwater and Burgess to arrest a hoarder where they discover more than just clutter.

Atwater and Burgess 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 overprotective act with Lindsay leads her right where he doesn’t want as she also helps to keep Justin out of trouble. Meanwhile on stakeout, things get tense between Olinsky and Ruzek as Olinski tries to teach him the finer points of surveillance.

Voight and Antonio enlist the help of agents at the Special Victims Unit in New York, Fin and Rollins, to help track down the culprit of a series of rape/murders. Burgess has an opportunity to prove herself to Intelligence. Elsewhere Lindsay enlists the help of Halstead to act as her date for her high school reunion to get back at an old rival.

The crossover starts on Law & Order: Special Victims Unit S15E15 Comic Perversion (I).

Voight's son may be involved with the Fitori murder case, intensifying tension between Antonio and Voight; Ruzek helps Burgess get retribution.

Voight is assigned a new Internal Affairs handler, Stillwell 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. At the same time Halsted remains fixated on Lonnie Rodiger and enlists Jin’s help to gather more information. Meanwhile, Ruzek’s inflated ego leads Olinsky to take him down a peg and offer a great opportunity to Atwater.

In responding to a call Atwater and Burgess discover a gunshot victim and the only witness is Lexi Olinsky. The shooting is tied to a Latin gang. To protect Olinsky’s daughter, Voight takes the case from the Gang Unit. Ruzek pulls up Burgess to help with an undercover mission that he hopes will help solve the case. Jon Seda, Sophia Bush, Jesse Lee Soffer, and Archie Kao also star.

Halstead's badge is revoked when Lonnie Rodiger is found dead; Severide and Clarke find Dr. Elliot's torso; Sumner tries to prove herself; Lindsay shares a moment with Severide.

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, 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. Meanwhile, a softer light is cast on Platt when she enlists the help of Ruzek.

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. Meanwhile Burgess sits vigil for her niece whose life hangs in the balance.

The crossover starts on Chicago Fire S02E20 A Dark Day (I).

Commander Perry notifies the Intelligence unit that Pulpo 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 gets some difficult news as a blast from Lindsay’s past comes back, giving us a glimpse at where she came from. Voight reminds her that she’s come too far to screw it up. At the same time we learn something about Jin that is bound to be a problem.

As Antonio’s life is now in question, Voight and Platt 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 back in town Lindsay realizes she’s going to have to come clean about a few things. Halstead finally gets answers he’s been wanting about Voight’s and Olinsky’s past.

Atwater is settling into his new gig on intelligence as Antonio is relegated to desk duty while recovering. Lindsay finally realizes she has no way out and confides in Voight for help. Meanwhile Jin is confronted about his secret meetings with Stillwell.

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. Burgess meets her new partner, Sean Roman and tension is high from the start, and she soon 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.

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. Burgess and Roman investigate a series of house break-ins and get some help from Desk Sgt. Platt.

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. Voight and the team keep this investigation in-house to find the hired assassin. After a tense interaction at district, Platt and Nadia come to an understanding.

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. Platt puts Roman and Burgess on gun buy-back duty where they ask questions when they aren’t supposed to.

While trying to help out, Olive Voight is attacked and taken. Ruzek and Atwater prove they belong on the team when they demonstrate smarts and savvy tracking down a lead that will hopefully bring them to Voight. Burgess and Roman try to track down a girl who runs off with a police badge.

Following the death of a 10-year old girl, the intelligence unit has one option to gain access to their suspect. Voight and Olinsky follow-up on a good lead to answer some questions about the shooting. Burgess and Roman show three boys around district thinking they are part of the Police Explorers program.

The intelligence unit is joined by detectives from New York’s SVU to help solve the pedophile ring case. Ruzek, Amaro, Halstead and Antonio continue to hunt for the link to foster care and child trafficking. Burgess and Roman try to find the shooter from the hospital after using surveillance footage to identify him. Platt shows her deep respect for police and the dangerous work they do by honoring their fallen brother.

The crossover starts on Chicago Fire S03E07 Nobody Touches Anything (I) and Law & Order: Special Victims Unit S16E07 Chicago Crossover (II).

While Antonio continues his off-duty security job for Asher and Layla, Asher is killed. While they work the case, Halstead and Lindsay go undercover in a rather uncomfortable location. Kot shows up to ask Lindsay for an answer.

A friend of Nadia’s leads the intelligence unit to a huge heroin bust. Unfortunately this bust results in Olinsky arriving home to find the suspects are holding his wife. Voight and the team think they’ve found a common thread with the suspects but it’s not who they think. Meanwhile Burgess and Roman are given an assignment where they get paired with a K-9 officer, Jenn Cassidy who is Roman’s former partner and girlfriend.

With Burgess in the hospital after suffering gunshot wounds, the intelligence team is determined to find the people responsible. Lindsay delays her start on the federal task force 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.

Lindsay has her first case with the task force and realizes she needs to call on Voight and the Intelligence unit to assist. Meanwhile Burgess is back on the job, but relegated to desk duty which allows Desk Sgt. Platt the opportunity to partner up with Roman.

Bob Ruzek is the first to arrive on the scene of a double murder. Intelligence arrives to take over the investigation and tensions arise as Bob needs to hand over the case to his son and Voight. Lindsay's new gig has her planning a trip to Bolivia for an undercover investigation that could be for an extended amount of time. Burgess and Roman realize they need to put past events behind them so it doesn't jeopardize them going forward.

Antonio and his sister Gabriela go to the office of Elliot Gish, the man they believe started the fire that killed Shay. Intelligence, along with patrol officers Burgess and Roman, put pressure on Gish to confess. Lindsay approaches Voight about returning to Intelligence when she realizes that the task force isn’t what she thought it would be. Desk Sgt. Platt has everyone curious why she’s being overly cheery, friendly and nice.

The crossover starts on Chicago Fire S03E13 Three Bells (I).

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.

Burgess begins to regret her recent decision to stay on the beat. While at a convenience store she sees some suspicious activity and pursues it without calling in for backup. It's a slow day in Intelligence as they spend their time receiving taser certification.

Antonio heads undercover with a dangerous robbery crew after a narcotics officer goes missing.

When a murder implicates a diplomat, the FBI stands between Intelligence and justice.

When Voight's card ends up in the hands of a murder suspect, he aims to protect the man at any cost.

Led by Olinksy, Intelligence hunts down an elusive Chinatown gangster.

SVU's Benson, Fin and Amaro help with the investigation of a rape-murder that's similar to a decade-old case in New York; and, after he's questioned, a suspect warns Lindsay that the investigation could have unintended consequences.

The crossover starts on Chicago Fire S03E21 We Called Her Jellybean (I). It continues on Law & Order: Special Victims Unit S16E20 Daydream Believer (III).

The investigation into the bombing of a trendy café hinges on a minor who witnessed it. A major blunder lands Atwater in hot water. Voight helps Platt in her attempt to get a memorial stone for the team's fallen member.

A mass shooting at an athletic club is investigated; and Atwater, who's dealing with his new assignment, helps locate the suspected shooters. Platt and Halstead, meanwhile, check in with Lindsay to see how she's managing.

Retired Commander Perry enlists Voight and the team to help extract his cop nephew from a unit of corrupt officers who are robbing drug dealers. When things go bad Voight must take down a younger, more violent version of himself. Meanwhile, Lindsay struggles to stay clean. At the same time a woman from Olinsky's past reaches out to him.

A bust to bring down a heroin kingpin goes horribly awry. Olinsky reveals a dark secret from his past, and Halstead tries to get through to a spiraling Lindsay.

A child abduction case hits too close to home for Dawson. Lindsay and Bunny's relationship reaches a critical impasse and Roman reveals his secret to Burgess.

The team is terrorized by a gun-wielding father who is desperate to find his missing daughter. Bunny stirs up accusations of misconduct from Voight's past.

Voight seeks revenge on the man who tried to kill him. A rumor causes a rift in Intelligence.

Ruzek's job is on the line after an ill-fated undercover op.

The team investigates a band of rogue operatives.

The team investigates a Columbine-like threat at a private school. Atwater seeks out a mentor; Olinsky's marriage faces a crisis.

The team discovers the mutilated body of a government official while responding to an informant's tip about an upcoming drug trade. Meanwhile, Burgess helps plan a surprise for Platt.

The discovery of a headless body in Lake Michigan points to Hank's mob connections. Roman risks everything to help a grieving mother.

Intelligence investigates a doctor who gave his patients lethal doses of chemotherapy. Roman fights a wrongful shooting investigation.

The crossover starts on Chicago Fire S04E10 The Beating Heart (I) and Chicago Med S01E05 Malignant (II).

Intelligence hunts down a crew responsible for a rape and robbery rampage. Lindsay is abducted on an undercover operation.

Voight arranges for his former cellmate, Eddie Little, to be a CI in an effort to bring down a major cocaine supplier. Burgess makes a major move regarding her relationship with Ruzek. Roman develops a plan to help fund Platt and Mouch's wedding.

Lindsay goes undercover to catch a rogue cop who targets women at casinos. Platt risks her life in a negotiation crisis.

SVU joins Chicago P.D. in a manhunt for two notorious escaped serial killers.

The crossover starts on Law & Order: Special Victims Unit S17E14 Nationwide Manhunt (I).

While working at a sobriety checkpoint, Burgess finds a duffel bag full of heroin in the truck of a respected college professor who claims to know nothing about how the drugs ended up there. At District, Roman expresses his desires to become a Field Training Office to Platt, and Mouse sets Halstead up with an off-duty security job working for the attractive owner of a medical marijuana clinic.

When a young boy is executed, Intelligence turn to the boy's parents for information and upon further investigation, discover the father has a criminal background and was a part of a local gang.

While out on a bank run for his off-duty security job at the dispensary, Halstead and his co-workers find themselves under attack by a violent robbery crew. Meanwhile Roman, Burgess, Antonio, Halstead, Ruzek and Atwater follow-up on a lead and track down a potential suspect.

While responding to a call of shots fired, Voight, Antonio, Halstead and the team come across a secret battered woman's shelter and discover the owner has been wounded and a resident of the shelter has been kidnapped. Burgess and Roman go undercover to track down a man robbing people by catfishing them on a dating app. Lindsay opens up to Halstead about her past.

When Burgess and Lindsay respond to a call about a stabbing, the assailant turns out to be a kidnapping victim escaping her captor; Ruzek accuses Roman of having feelings for Burgess.

Responding to a call about a suspicious duffel bag at the Chicago Lakefront, Voight is horrified to discover that the bag contains the frigid and unmoving body of a newborn baby. Meanwhile, Voight is surprised to hear that his son is in town and Burgess and Roman grow closer.

Burgess gives chase after Roman is wounded by a hooded perp who opened fire on their patrol car and shoots who she thinks is the suspect, but no gun is found at the scene—and the person she shot is a 17-year-old honor student.

Lindsay and Halstead respond to a shots fired call and discover one survivor: a young girl. Antonio and Olinsky investigate a "self help" group. Platt makes the case to Crowley for why Burgess and Roman should remain partners.

In the Season 3 finale, the team investigates the murder of a single mom who was in contact with Voight's now-reformed son, who was himself brutally assaulted. Meanwhile, Roman makes a major decision and Crowley plans to make changes within the unit.

The team investigates a murder in which the victim appears to have been wearing a CPD-issued wire. Burgess works a case with a new partner. Crowley questions Lindsay about the night that Intelligence pursued Justin's killer.

Intelligence investigates when a young man is beaten and his fiancée is apparently abducted. Lindsay surprises Halsted with a big question. Cdr. Fogel takes Platt to task for going over his head to have Tay assigned to District 21.

Platt is sent to the hospital after a vicious attack outside her father's house. Mouch is questioned and past threats against her are revisited while the team investigates. A gruesome discovery inside the father's home ups the ante in the case.

A car plows through a crowd outside of a concert venue and is followed by gunfire, sparking fears that it may be terror-related. Burgess spots Atwater's brother where he shouldn't be. The team works to bring peace to the community before more blood is shed.

The team hunts drug dealers selling fentanyl, which has been linked to multiple overdoses around the city. Tay and Burgess discover a bloodied child who shares a twisted secret about his home life. Mouse contemplates reenlisting in the Army. Platt informs Tay about her next assignment.

After receiving a complaint from a frustrated neighbor, Burgess and Officer Sorensen arrive to the house of baseball player Jake McCoy, and find the dead body of a 16-year-old girl, Maya Collins. There is conflict within the case as Intelligence learns that Olinsky and McCoy are friends, and McCoy admits that he was helping Maya and other girls try to escape the sex trade. Meanwhile, Burgess and Sorensen track down a thief who turns out to be a cop with a rocky past, and Lindsay gets a mysterious flower delivery that may be tied to her past.

Voight calls the team to investigate a homicide involving the only witness in a rape and murder case against an extremely young man, Oliver Tuxhor. 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 offers Antonio a job as lead investigator for the state attorney's office, and Burgess and Sorensen's 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.

Severide is brought into the District for questioning after his car is found to have caused a deadly crash. As the investigation gets underway, the team works to uncover a group of car-jackers who may be the key to Severide's innocence.

The crossover starts on Chicago Fire S05E09 Some Make It, Some Don't (I).

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.

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.

After a female jogger is brutally murdered in the park, Rixton and Atwater arrive to see two suspects fleeing the scene. When the men make their way inside a church, the priest and parishioners gather outside to block law enforcement from entering. While investigating the case, Rixton gets caught in a lie with Voight.

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 sends Halstead 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.

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 and Halstead receive an odd warning about Rixton that leaves them suspicious.

When Lindsay is tipped off about a grieving father looking to avenge his daughter's death, Olinsky goes undercover as a hitman-for-hire. With Gang Intelligence lacking enough evidence to arrest the original gangbanger in question, the team works to reinvestigate the case. Meanwhile, Ruzek comes back after finishing his undercover assignment only to have Voight knock him down to patrol duty.

Olinsky's daughter remains in critical condition following a massive fire - leaving Intelligence on edge, but more determined than ever to track down the suspect. Voight opens up the case, knowing that he has Stone and his team's full support in the investigation, and all of Firehouse 51 behind him to examine potential origins of the fire.

The crossover starts on Chicago Fire S05E15 Deathtrap (I). It continues on Chicago Justice S01E01 Fake (III).

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 questioning the legitimacy of the case, and sends the team on a twisted trail to get to the bottom of it.

When Chicago's "Night Crawler" Bobby Trent is murdered over a single piece of mysterious footage, Intelligence must investigate one of Chicago's wealthiest families. Meanwhile, Burgess's sister Nicole arrives at the District for a visit, and presents an icy attitude towards Ruzek.

After encouraging her sister to spend a night out with friends, Burgess wakes to find that Nicole 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.

While investigating the murder of a teenage boy, Voight finds a connection with the murder weapon - linking it to a case that he worked on 17 years ago. While the victim's father, 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.

When the team is called to an in-progress bank robbery, they come across Detective Hailey Upton trying to take over the crime scene with her Robbery-Homicide unit - butting heads with Voight in the process. As the robberies continue to be executed around the city, Lindsay is forced to make a decision in the heat of the moment.

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.

When Lindsay receives a panicked call from her mother Bunny 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.