The department and community press the Homicide Unit to solve a cop-involved killing. With the lives and reputations of fellow officers at stake, Giardello clashes with Pembleton over the investigations. Giardello demands pursuing civilian suspects, but Pembleton's instincts tell him the cops are lying. Other personal relationships are challenged when Munch gives his girlfriend a present recovered at a crime scene that meets with disastrous results. Heartstrings are pulled when Bolander meets a waitress at the local coffee shop who shares his love of playing music.