Detective Brian Michael Walsh, New York City's top homicide detective, once again enters the world of the blue-eyed man-a world that did not treat him so well the last time he visited. Walsh stumbles on what he thinks is a plot to assassinate the president of the United States, but he cannot convince anyone at the Secret Service to take him seriously as he cannot produce one single piece of evidence to prove his theory. Walsh believes that a referee, who belongs to a secret organisation Walsh is not sure really exists, has been sent to assassinate President Cyrus Wilson on Walsh's home turf. He begins his own investigation but is thwarted at every turn, until the blue-eyed man himself crosses Walsh's path. What follows is a series of events that destroys the reputation of the Secret Service, and has Walsh and his squad of detectives once again hunting the referee, the most cunning and deadly opponent they have ever faced.