Harlee navigates her fractured relationship with Wozniak, as she struggles to conceal her deepest secret. Following his discovery that Harlee collaborated with the FBI, Wozniak is confronted with a gut-wrenching dilemma of his own. The crew is under tight scrutiny from Stahl and the FBI as well as from Internal Affairs. Meanwhile, a former member of their crew, Julia Ayres, runs for mayor and neither Harlee nor Wozniak anticipates that Ayres’ corrupt connections will trap them in a dangerous war with the Mafia.