Errol Flynn as Sebastian Dubrok

Ida Lupino as Gemma Smith

Eleanor Parker as Fenella MacLean

Gig Young as Caryl Dubrok

Reginald Denny as Mr. MacLean

Isobel Elsom as Mrs. MacLean

Albert Bassermann as Professor Heinrich

Ludwig Stössel as Mr. Steinach

Milada Mladova as Natrova

George Zoritch as The Dancer

Helene Thimig as The Landlady

Frank Puglia as The Guide

Frank Reicher as The Minister