The outbreak of World War I places Scots officer Geoffrey Richter-Douglas in an uncomfortable position. Although his allegiance is to Britain, his mother was from an aristocratic Bavarian family, and he spent his summers in Germany as a child. When Geoffrey is approached by a German spy who offers him a chance to defect, he reports the incident to his superiors, but instead of arresting the spy they suggest that he accept her offer--and become an Allied agent. In Germany, among old friends, Geoffrey discovers that loyalty is more complicated than he expected, especially when he finds himself aboard the maiden voyage of a powerful new prototype Zeppelin, headed for Scotland on a secret mission that could decide the outcome of the war.
Practical Effects
Full-scale zeppelin interior sets are genuinely impressive for 1971.
Costume
Elke Sommer's spy wardrobe is doing absolutely all the heavy lifting.

Director
Étienne Périer
Trivia, insights & behind the scenes
The production built a 60-foot partial zeppelin exterior for location shooting, which local Scottish residents reportedly mistook for a real aircraft in distress.
Released during the peak of Michael York's 'accidentally sexy in period pieces' era, between Cabaret and The Three Musketeers.