Chicago P.D.

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.

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.

When Platt (Amy Morton) goes to her father Robert's (guest star Chelcie Ross) house for dinner, she warns him to be careful with his new girlfriend Natalie (guest star Lilia Vassileva). Following dinner, Platt is physically assaulted as she's getting into her car and is rushed to Chicago Med. Voight (Jason Beghe), Lindsay (Sophia Bush) and Halstead (Jesse Lee Soffer) arrive at the hospital to investigate, and a concerned Mouch (guest star Christian Stolte) finds himself being questioned. Meanwhile, Antonio (Jon Seda) leads the rest of Intelligence at the scene as they look into previous threats against Platt, but his attention shifts when he is called into Robert's townhouse and finds signs of an even more gruesome attack on Platt's father.

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 is tasked with tracking down the dealers of fentanyl a drug that has been linked to multiple overdoses around the city. As they investigate possible sources, the team uncovers a series of dealers in a college smuggling ring. Meanwhile, Tay (guest star Li Jun Li) and Burgess (Marina Squerciati) come across a bloodied child who exposes a dark and twisted secret about his home life with his parents. Additionally, Mouse (guest star Samuel Hunt) causes tension as he looks to reenlist in the army, and Platt (Amy Morton) tells Tay (guest star Li Jun Li) that she has been reassigned to her original post.

After receiving a complaint from a frustrated neighbor, Burgess (Marina Squerciati) and Officer Sorensen (guest star Kevin Kane) arrive to the house of baseball player Jake McCoy (guest star Billy Burke), and find the dead body of a 16 year old girl, Maya Collins (guest star Violett Beane). There is conflict within the case as Intelligence learns that Olinsky (Elias Koteas) 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 (Sophia Bush) gets a mysterious flower delivery that may be tied to her past.

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.

Severide (guest star Taylor Kinney) 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. Meanwhile, Voight (Jason Beghe) pairs Burgess (Marina Squerciati) with Olinsky (Elias Koteas), who has a hard time feigning his excitement about this new partnership, and Lindsay (Sophia Bush) considers meeting her estranged father who is now out of prison.

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.

After a female jogger is brutally murdered in the park, Rixton (guest star Nick Wechsler) and Atwater (LaRoyce Hawkins) 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 (Jason Beghe).

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.

When Lindsay (Sophia Bush) is tipped off about a grieving father looking to avenge his daughter's death, Olinsky (Elias Koteas) 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 (Patrick John Flueger) comes back after finishing his undercover assignment only to have Voight (Jason Beghe) knock him down to patrol duty.

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).

When Chicago's "Night Crawler" Bobby Trent (guest star Michael B. Woods) is murdered over a single piece of mysterious footage, Intelligence must investigate one of Chicago's wealthiest families - uncovering a lineage of old money and secrets. Meanwhile, Burgess's (Marina Squerciati) sister Nicole (guest star Jules Willcox) arrives at the District for a visit, and presents an icy attitude towards Ruzek (Patrick John Flueger).

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).

When the team is called to an in progress bank robbery, they come across Detective Hailey Upton (guest star Tracy Spiridakos) trying to take over the crime scene with her Robbery Homicide unit butting heads with Voight (Jason Beghe) in the process. As the robberies continue to be executed around the city, Lindsay (Sophia Bush) is forced to make a decision in the heat of the moment, revealing a surprising suspect behind the mask. While working on the case at the district, Upton is shocked to come across Platt (Amy Morton), who has a special connection to her past.

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.

Prepare for Season 4 of Chicago PD with highlights from Season 3's intense finale.