In Memphis, a well-loved neighborhood investor is shot, and the only eyewitness is a young girl on her way home from school. Sgt. Mitch Oliver and his team must persuade the girl's mother to let her talk to police. And in Miami, the murder of a homeless man appears to involve the notorious MS-13 gang. Detective Aguilar and his team follow a mysterious trail of graffiti that they hope will lead to the killer.