When Detectives Cyrus Lupo and Kevin Bernard arrive on the scene of four fallen police officers, they have to act fast to find the shooter. With a room full of witnesses, they have a description of the culprit but little else. The case becomes even more complex when the detectives discover that the police officers may have known the shooter. The investigation quickly leads them to a circuit of drug dealers, a jealous husband and a remorseful judge who are all pieces of a larger puzzle.