James Patterson has created a suspenseful, twisty, and easily readable tale of crime, revenge, and the inevitable conflict between a mentally ill and obsessed serial killer and those in law enforcement who are driven to identify and stop him before his rampage continues. Seemingly unrelated crimes in two separate communities are quickly linked by the killer's "calling card," the insignia of Chimera, a Greek mythological two-headed monster, which is eventually identified as the symbol of a vicious, white supremacist group, operating both within and outside of prisons. The killings continue and the eventual connection to police officers is made.

As Lindsay Boxer, Lieutenant in the San Francisco homicide department sets out to bring the killer to justice, she is joined by three friends, an Assistant District Attorney, the Medical Examiner, and a reporter for the San Francisco Chronicle, all four of whom have recently solved another vicious serial murder spree. Each has a part to play in the investigation, including dogged police work, research into police personnel files and newspaper archives, and autopsies that provide valuable clues regarding the killer's weapons, marksmanship abilities, and the existence of a tattoo on his chest. Lindsay and fellow officers follow the trails of evidence, but the killer is always one step ahead, and the frustration only ends when thorough analysis of the few clues leads to a former police officer, Frank Coombs, who, twenty years earlier, had been convicted of manslaughter in the murder of a young black boy. The search for Coombs and his ultimate death on the steps of Justice Hall, as he attempts to kill Lindsay, provide temporary relief to both the department and the public, both of whom are now assured that this racist, mentally ill, vengeful murderer has been brought to justice.

The satisfaction is short-lived, however, as Chimera strikes again and as Lindsay realizes that the autopsy evidence on Coombs does not fit the true killer. The final conclusion that the true Chimera killer is Combs's son, a model college student/athlete, is a shock to all, but, as he is pursued, the reader is given the final pieces of information which demonstrate that he, in fact, is as mentally ill and as obsessed with revenge as his father. The final moments of the killer's life involve a shoot-out between Lindsay and him at the top of a tower, with throngs of people below and the excruciating peeling of carillon bells.

Interspersed throughout the work are important comments on society's institutions, to include police departments and the justice system in general, as well as on continuing social issues of racism, terror, and the criminally insane. As Lindsay struggles over the relationship with a father who has re-entered her life after twenty years, as Jill Bernhardt struggles with the conflict between a career and a desire for children, and as Cindy begins a new relationship with a black church pastor, realistic and natural issues of personal lives, though minor events, serve to lend credibility to the characters being portrayed.