Bill Dietrich becomes a double agent for the F.B.I. in a German spy ring.

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?—Rod Crawford <[email protected]>

Prior to the United States entering WWII, the FBI is monitoring known and suspected Nazi agents in the country. Purely by happenstance, they discover a Nazi cell in the US trying to smuggle information back to Germany on Process 97, a key part of the American atomic bomb development. The FBI's Inspector George Briggs leads this case, known as the Christopher Case as the unknown leader of the Nazi cell has the code name Mr. Christopher. Briggs' team cannot just bring in the known Nazi agents, but rather they have to find out exactly how the information is being leaked and who Mr. Christopher is. They co-opt the assistance of William Dietrich, a German-American university student who the Nazis tried to recruit. As such, he will be working for the FBI as a double agent (i.e. he will go along with the Nazi recruitment plan). Unknown on either side, it becomes a race as Dietrich's Nazi contacts in the United States, led by Elsa Gebhardt (fronting as a women's gown designer), don't fully trust him and come ever so close to discovering his double agent status, while Briggs, Dietrich and their associates close in on the leak and the identity of Mr. Christopher. The modi operandi for both sides change slightly with December 7, 1941.—Huggo