The story begins with highly decorated Detectives Turk and Rooster of the NYPD facing a retirement which neither of them are ready for. Before they can hang up their badges, they are called to investigate the murder of a notorious pimp, who appears to have ties to a case they solved years before. Like the original murder, the victim is a suspected criminal whose body is found accompanied by a four-line poem justifying the killing. When additional crimes take place, it becomes clear the detectives are looking for a serial killer - one who targets criminals who have fallen through the cracks of the judicial system. His - or her - mission seems to be what the cops aren’t able to do: take the culprits off the streets for good. The similarities between the recent killings and their earlier case raise a nagging question: Did they put the wrong person behind bars?