Dov and Andy cover a music festival where a girl ends up dead due to drugs. Gail goes to court and is unsure whether lying for her brother is the right thing to do. Nick gives Juliet another chance.
Andy, Dov, Gail and Nick undertake a risky plan; Traci shadows Steve Peck, hoping to calm her fears about his involvement in the bombing.
A community-outreach baseball game is interrupted by a drive-by shooting. Sam plans a getaway with Andy.
Andy and Sam are shocked to learn that Oliver is the prime suspect in IA’s corruption investigation into 15 Division. What’s worse, they only have until end of day today to find Chris Klem – the missing explosives-dealer – and clear Oliver’s name before he takes the fall.
Nick receives new information on his tragic past, and goes off the grid to track someone down; Nick is forced to tell Juliet about his secrets.
Andy contemplates her future with Sam after learning heartbreaking news. Andy meets a teen in need of protection.
Andy and Sam return to work; Andy is attacked at Traci's place and Sex Crimes Unit tries to take over the case
Ambitious young cops try to prove themselves in their high-stakes careers, in which the smallest mistake can have deadly consequences. At the core of the close-knit group is perfectionist Andy McNally, whose father was a homicide detective before he burned out on the job. The series follows Andy and her four colleagues -- Dov Epstein, Gail Peck, Traci Nash and Chris Diaz -- as they experience the trials, triumphs and tribulations of police work, as well as its effect on their personal lives.