In this latest case, Private Detective Shawn McCormick is called upon to help solve a double homicide by a trained assassin and, subsequently, rush to the aid of the woman who witnessed the crime. This requires him to travel to the state of New Mexico, where he discovers a well-organized plot to cover up, not only the murders, but the identity of the killer he is pursuing. Follow along as McCormick and his companions risk it all to track down and solve the mystery surrounding ... the Fourth Man.