In 1941, the Nazis have overrun Europe, England is under siege, and relations with Japan have deteriorated. U.S. involvement appears imminent. Los Angeles Deputy District Attorney Earl Grady has been assigned to a Public Safety Committee run by the FBI to alert local law enforcement agencies to the espionage activities of Japanese residents. When a prominent committee member is found murdered just hours before the Pearl Harbor attack, the FBI promptly concludes that the killers are Japanese spies. What else could explain finding the victim's body impaled by a samurai sword?

Fear grips the West Coast-radio broadcasts are halted, blackouts are implemented, and Japanese submarines begin attacking commercial vessels within sight of the shoreline. Beach lifeguards, symbolic of Southern California's carefree lifestyle, now find themselves patrolling the deserted sands armed with pistols. With California's elected officials clamoring for the mass relocation of all Japanese people, the overworked FBI puts a low priority on uncovering the identity of the killers.

Driven by curiosity, Grady enlists the help of two Japanese American students who are desperate to show their loyalty. Will this unlikely team be able to solve the crime while coping with the fearsome uncertainties of a once-idyllic place now being called "a theater of operations?"