Agent Andy Clayton has been inactive for eighteen months, kept under tight surveillance at his home in Washington D.C. Now he is needed—Leonid Borikowski, code name Dragonfly, has been seen entering the U.S., and Clayton is the only man who may be able to find and stop him. For Clayton, it is much more than a routine assignment. He knows Dragonfly, has faced him before, and he wants him. His interest is as personal as it is professional: He wants revenge on the foreign agent who killed Duncan Clayton, his twin brother. But there is much that Clayton doesn't know. He doesn't know that Borikowski is carrying perhaps the most important, and dangerous, biological discovery the world has ever known. He doesn't know that the microbe is in a suitcase armed with a device that will explode if Borikowski is harmed. And he doesn't know about the Soviet intelligence project code-named Bookends—a project that will not be complete until Andy meets the same fate as his brother. The ensuing chase takes him across the United States and Canada, putting himself, the woman he loves, and thousands of innocent people in jeopardy.

The setting is Carmel, California—a scenic, peaceful tourist haven where James Dewitt is the police force's only detective. His usual caseload is stolen bicycles and an occasional burglary, but things change with frightening speed when a series of apparent suicides, which soon prove to be murders, shocks the community. Dewitt, a former forensic scientist, struggles with the minutest of clues in his quest for the killer, while departmental turf wars and local politics increase the pressures on his investigation. His steps are further dogged by renegade ex-cop Howard Lumbrowski, the man Dewitt blames for his wife's death. How is Lumbrowski connected to the killings? And why does he have information from Dewitt's confidential files? Dewitt finds himself playing a dangerous game, breaking his own rules in a desperate search for answers.