It begins when the naked body of a businessman is discovered in a bathtub surrounded by a bizarre selection of props left behind by the killer as a taunt to law enforcement. Two more murders with similarly staged scenes connecting them to the first soon follow. Recruited to join the investigation against their will, Mal and Vinn are drawn into the dark world of genius-level puzzle addicts and a killer who challenges them with riddles. They soon discover a pattern that teases the occupations of both future killers and victims but reveals little else as they race to identify the person behind the murders before the carnage reaches their own inner circle. As the body count rises, they realize that justice can only be served outside of traditional law enforcement methods and that the ultimate solution will come at the cost of either their careers or their lives.