The House on 92nd Street is a 1945 black-and-white spy film directed by Henry Hathaway. The film, shot mainly in New York City, was released shortly after the end of World War II. The House on 92nd Street was made with the full cooperation of the Federal Bureau of Investigation (FBI), and its head, J. Edgar Hoover, appears during the introduction. Also, the FBI agents in Washington were played by actual agents. The film’s semidocumentary style inspired other films including The Naked City.
In 1939, American standout university student Bill Dietrich (William Eythe) is approached by Nazi recruiters due to his German heritage. He feigns interest, then notifies the FBI. FBI agent George Briggs (Lloyd Nolan) tells him to play along.
Dietrich travels to Hamburg, Germany, where he undergoes six months of intensive training in espionage. He is then sent back to the United States to set up a radio station and to act as paymaster to the spies already there. He is told that only a “Mr. Christopher” has the authority to change his assignment.
Dietrich manages to pass along his microfilmed credentials to the FBI; they are altered so that instead of being forbidden to contact most of the agents, he is authorized to meet them all. In New York, his contact, dress designer Elsa Gebhardt (Signe Hasso), is suspicious of the modification and requests confirmation from Germany, but communication is slow. In the meantime, she has no choice but to give Dietrich full access to her spy ring. When questioned, Dietrich’s other legitimate contact, veteran espionage agent Colonel Hammersohn (Leo G. Carroll), denies knowing Mr. Christopher’s identity.
In a separate development, a German spy is killed in a traffic accident; the FBI finds a secret message among his possessions stating that Mr. Christopher will concentrate on Process 97. Briggs is alarmed because he is aware that Process 97 is America’s most closely guarded secret.
When the Japanese attack Pearl Harbor in December 1941, the United States enters the war. Most of the spies Dietrich has identified are immediately picked up, but Gebhardt’s ring is left alone, in the hope of flushing out Mr. Christopher.
Gebhardt gives Dietrich papers to transmit immediately to Germany; they contain part of Process 97, a key part of the atomic bomb project. Dietrich steals a cigarette butt he notices in non-smoker Gebhardt’s otherwise empty ashtray. The FBI traces this tiny clue to Luise Vadja, and from her to her supposed boyfriend, Charles Ogden Roper (Gene Lockhart), a scientist working on the atomic bomb. Roper breaks when he is picked up and shown a message from Germany ordering his liquidation after he has completed his mission. Roper confesses to dropping off the last part of Process 97 at a bookstore, hiding the papers in a book. A man believed to be Mr. Christopher is filmed leaving the store. That is enough for Briggs. He orders the arrest of Gebhardt’s ring.
It is just in time for Dietrich. Gebhardt finally receives a reply from Germany, confirming her worst fears. She injects Dietrich with scopolamine in an attempt to obtain information, but her building is surrounded by government agents. Gebhardt orders her underlings to hold them off while she disguises herself as a man – she is Mr. Christopher – and tries to escape with the vital papers. Unable to get away, she returns, only to be shot by mistake by one of her own men. The rest are captured, and Dietrich rescued.