Warner Bros. was always a progressive studio when it came to dealing with social issues that their competitors shied away from. With the Nazi threat building momentum in Europe, the studio courageouly defied external pressures and made the first Hollywood film to expose the issue of domestic espionage. Based on true events, Edward G. Robinson stars as a government agent who uncovers a ring of Nazi spies operating in the U.S., with a fine supporting cast including Francis Lederer, George Sanders, and Paul Lukas.