In the series premiere, Teresa Colvin, Chicago’s city’s first female superintendent, lobbies for a city corruption task force to investigate city politician Alderman Ronin Gibbons. Meanwhile, Colvin’s ex-partner and larger-than-life veteran of the Chicago Police Department, Jarek Wysocki investigates a suspicious murder in Grant Park alongside his new partner, Caleb Evers. Also in Jarek’s charge are his niece, Vonda Wysocki; her hotshot partner, Isaac Joiner; and low-life Liam Hennessey, 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.

During a heatwave, Wysocki and Evers investigate a homicide where the son actually saw his father's murder. In the meantime, Colvin gets a new driver. And Gibbons reaches out to Liam to help him with his constituents.

FBI Special Agent Cuyler returns to see Superintendent Colvin; Jarek deals with family issues that have haunted him for years; and the case against Alderman Gibbons comes to a conclusion.