Working as a private investigator, Monk visits a crime scene to investigate the murder of Nicole Vasquez. He finds a number of significant clues, but is not yet sure of the identity of the murderer. Later, shots ring out at a campaign rally, and San Francisco mayoral candidate Warren St. Clair's bodyguard is killed. The incumbent mayor instructs Captain Stottlemeyer to bring Monk in on the case, and reluctantly, he does.
After a brief meeting with Warren St. Clair, his wife Miranda, and their aide Gavin Lloyd, Monk goes to the scene of the assassination attempt. Can the obsessive-compulsive detective solve an unsolvable case?