The action takes place during the Great War in the home of the First Lord of the Admiralty.
Constance Bennett
as Frances Hawtree / Z-1
Erich von Stroheim
as Valdar / Schiller Blecher
Anthony Bushell
as Capt. Arthur Chamberlain
William Courtenay
as Mr. Yates
Crauford Kent
as General Hewlett
Charlotte Walker
as Lady Catherine Chamberlain
William Holden
as Sir Winston Chamberlain
Paul Panzer
as 'Kirsch' the Decoy
Wilhelm von Brincken
as Capt. Kugler
Ullrich Haupt
as Colonel
