When his code book is stolen, a Nazi spy (J. Carroll Naish) — masquerading as a San Francisco optometrist during World War II — teams with a sadistic fellow operative (John Carradine) to keep it from landing in authorities’ hands and exposing a network of German sympathizers. But the duo’s complex scheme to recover the book hits a few snags in this fast-paced tale of espionage also starring Terry Frost and Maris Wrixon