"The second of the three film versions of the E. Phillips Oppenheim espionage thriller set largely in an old dark house where a tremulous wife wonders if her husband is really his double, a dastardly German spy."
Edmund Lowe
as Sir Everard Dominey / Baron Leopold von Ragostein
Valerie Hobson
as Eleanor Dominey
Wera Engels
as Princess Stephanie Elderstrom
Murray Kinnell
as Seaman
Henry Mollison
as Eddie Pelham
Esther Dale
as Mrs. Unthank
Brandon Hurst
as Middleton
Ivan F. Simpson
as Dr. Harrison
Spring Byington
as Duchess Caroline
Lumsden Hare
as Duke Henry
Charles Waldron
as Sir Ivan Brunn
Leonard Mudie
as Mangan
Claude King
as Sir Gerald Hume
Frank Reicher
as Dr. Trenk
Harry Allen
as Perkins
Nan Grey
as Middleton's Daughter (uncredited)
Willy Castello
as Duval (uncredited)
Priscilla Lawson
as Maid (uncredited)
Virginia Hammond
as Lady Hume (uncredited)
Thomas R. Mills
as Bartender (uncredited)
Tom Ricketts
as Villager (uncredited)
Frank Terry
Robert Bolder
Lowden Adams
as Waiter (uncredited)
Dwight Frye
as Roger Unthank (uncredited)
David Dunbar
as English Farmer (uncredited)
Frank Benson
Leonid Snegoff
as Wolff (uncredited)
Harry Worth
as Hugo (uncredited)
Adolph Milar
as German (uncredited)
Larry Steers
as Army Officer (uncredited)
Douglas Wood
as Lord Allison (uncredited)
Pat O'Hara
as Chauffeur (uncredited)
Alan Crosland
Director
Fred S. Meyer
Executive Producer
Frank Wead
Screenplay
Eve Greene
E. Phillips Oppenheim
Novel
Milton Krasner
Director of Photography
Franz Waxman
Music
Roswell A. Hoffmann
Assistant Camera
Charles Carroll
Sound Recordist
Camille Collins
Production Secretary