Set during World War I, Zeppelin stars Michael York as Geoffrey Richter-Douglas, a British defector who goes to work in the fledgling German airship industry. In truth, Richter-Douglas is a spy, who has feigned defection in order to steal the plans for the revolutionary new Zeppelin. Our hero goes under cover so well that, when he tries to inform his own government of a German plan to steal the Magna Carta and thus irreparably damage British morale, no one believes him! Marius Goring costars as the inventor of the Zeppelin, who is racked with guilt when he learns that his creation is to be used for underhanded purposes, while Elke Sommer plays Goring's wife, who ends up helping Richter-Douglas to thwart the robbery scheme.