During the Nazi occupation of Czechoslovakia, surgeon Dr. Franticek Svoboda, a Czech patriot, assassinates the brutal "Hangman of Europe", Reichsprotektor Reinhard Heydrich, and is wounded in the process. In his attempt to escape, he is helped by history professor Stephen Novotny and his daughter Mascha.

Brian Donlevyas Dr. Franticek Svoboda
Walter Brennanas Prof. Stephen Novotny
Anna Leeas Masha Novotny
Gene Lockhartas Emil Czaka
Dennis O'Keefeas Jan Horak
Margaret Wycherlyas Ludmilla Novotny
Nana Bryantas Mrs. Hellie Novotny
William Royas Boda Novotny
Hans Heinrich von Twardowskias Reinhard Heydrich
Alexander Granachas Gestapo Insp. Alois Gruber
James Wong Howe