Preface: a stentorian narrator tells us that the USA was flooded with Nazi spies in 1939-41. One such tries to recruit college grad Bill Dietrich, who becomes a double agent for the FBI. While Bill trains in Hamburg, a street-accident victim proves to have been spying on atom-bomb secrets; conveniently, Dietrich is assigned to the New York spy ring stealing these secrets. Can he track down the mysterious "Christopher" before his ruthless associates unmask and kill him? Written by Rod Crawford