In a story based on actual events, Nazi spies in New York City try to recruit German-American college student Bill Dietrich (William Eythe) at the height of World War II. Dietrich instead offers his services to the FBI as a double agent. Infiltrating the spy ring, which is headquartered in an East 92nd Street townhouse, Dietrich must contend with the house's beautiful owner (Signe Hasso) and, ultimately, a cache of smuggled atomic secrets that could derail the entire American war effort.