In the series premiere, Teresa Colvin (Jennifer Beals), Chicago’s city’s first female superintendent, lobbies for a city corruption task force to investigate city politician Alderman Ronin Gibbons (Delroy Lindo). Meanwhile, Colvin’s ex-partner and larger-than-life veteran of the Chicago Police Department (CPD), Jarek Wysocki (Jason Clarke) investigates a suspicious murder in Grant Park alongside his new partner, Caleb Evers (Matt Lauria). Also in Jarek’s charge are his niece, Vonda Wysocki (Devin Kelley); her hotshot partner, Isaac Joiner (Todd Williams); and low-life Liam Hennessey (Billy Lush), an Irish thug who blends in with the gritty world of local crime. Together, these cops stop at nothing navigating the Windy City’s underbelly to fight crime and bring down Alderman Gibbons’ empire of corruption.
Following the shocking events related to a fallen officer, Teresa and Jarek vow to bring whoever is responsible to justice. In the meantime, Alderman Gibbons pays a visit to the victim’s family to offer his condolences and plant a few seeds of betrayal, implicating members of the Chicago Police Department. As every officer in the city hits the streets to avenge this cop killer, Jarek and Caleb follow up on some of Liam’s leads, while Vonda and Isaac are promoted to the organized-crime task force.
Jarek and Caleb arrive first on the scene at a bank robbery and chase the thief through the streets of Chicago only to find he has met a gruesome end. As the Chicago Police Department pieces together the clues of the robber, Superintendent Colvin conducts a critical meeting with Alderman Gibbons about a key construction site. Duplicitous politicking raises the stakes and further exposes the depth of corruption in the city.
After a bomber blows up a city building, additional targets and innocent people remain in danger. Teresa handles the escalating crisis, as Jarek and Caleb race against time to track down the suspect who might have ties to the Chicago Liberation Army. Meanwhile, Alderman Gibbons takes matters into his own hands when an armed teenage robber threatens him, which triggers a reflection on his own youth and upbringing when he was more of an idealist.
After a teenage boy is brutally murdered while spreading the word of his church in Chinatown, Detectives Wysocki and Evers enlist Superintendent Colvin to gain the cooperation of locals. When the unofficial mayor of Chinatown is uncooperative, Alderman Gibbons is called upon to broker a deal that accelerates the investigation. Meanwhile, Teresa's brother-in-law rolls the dice with a shady business deal, and Liam goes even deeper undercover.
When Superintendent Colvin calls upon Detectives Wysocki and Evers to locate a drug supplier who sent the son of an influential couple into a drug-induced coma, they uncover a more elaborate murder case. As the evidences stacks up, a downtown club where rich men and pretty women mix becomes the focal point of the case. Meanwhile, Teresa has her eyes set on securing funding to buy the department new radios.
The detective duo of Jarek Wysocki and Caleb Evers investigates an international drug dealer whose family is in jeopardy. FBI Division Chief Cuyler intervenes, complicating the high-profile case. While visiting grieving families with Alderman Gibbons, undercover cop Liam Hennessey becomes increasingly vulnerable when he feels the pain of victims. The family drama follows Jarek home when he visits his ex-wife, and wedding bells continue to ring for his fiancè.
The record-breaking summer heat and the likelihood of blackouts send the Chicago Police Department into the streets in full force to temper the city’s escalating violence. Alongside her new driver, Superintendent Teresa Colvin (Jennifer Beals) finds herself back in the field while Detectives Wysocki (Jason Clarke) and Evers (Matt Lauria) take over an emotional case in which a son witnessed his father’s fatal shooting. Meanwhile, Alderman Gibbons (Delroy Lindo) enlists Liam (Billy Lush) to help keep his constituents cool.
When five merchants are gunned down in a restaurant in Lincoln Park, key evidence points to an incarcerated gang leader from the impoverished neighborhood. Relentless press coverage prompts the embattled mayor to blame the city's rising crime problem on Superintendent Colvin, who, in turn, unleashes Jarek and Caleb to catch the killers in hopes of restoring her credibility as a competent leader. Meanwhile, Isaac and Vonda are forced to revisit a past domestic violence case.
While Teresa (Jennifer Beals) and Jarek (Jason Clarke) set the stage for their case against Alderman Gibbons (Delroy Lindo), their effort to clean up Chicago takes an unexpected turn when a deadlocked jury acquits a corrupt city official (guest star Bruce Nozick). Suspicious, the two mount an investigation, only to discover that jury tampering is just the tip of the iceberg.
Following a murder that appears to be a hate crime, Teresa risks tipping Gibbons off to her big-picture plan by boldly taking on the Chicago Police Department’s corrupt “meritorious” promotion system. Meanwhile, Jarek is forced to face his own reality when Vonda (Devin Kelley) receives an anonymous package that reveals more about the Wysocki family.
The case against Alderman Gibbons escalates, and Teresa, Jarek and Caleb (Matt Lauria) scramble to locate a star witness. As undercover cop Liam Hennessey (Billy Lush) continues to assemble evidence, he’s forced to take matters into his own hands.
It’s the moment of truth for the city of Chicago and the Chicago Police Department. FBI Special Agent Cuyler (guest star Adam Arkin) returns to pay Superintendent Colvin a visit, and Jarek stops at nothing to address family issues that have haunted him for years. When Jarek and Teresa are forced to put everything on the line, the stakes are raised as their case against the kingpin of corruption in Chicago comes to a climactic conclusion.