Professor Davidson (Frank Shannon) and his daughter Diana (Jeanne Bates) search Africa for the Lost City of Zoloz, reputed to be the source of a large hidden treasure. Also searching is a local crook, Singapore Smith (Joe Devlin), and Dr. Max Bremmer (Kenneth MacDonald), a Nazi agent who plans to destroy the peace in which the native tribes have been living and build a secret German airbase at Zoloz. But Diana’s fiancé Godfrey Prescott (Tom Tyler), who is also The Phantom, feared and respected by the natives as The Ghost Who Walks, circumvents the traps and schemes of the villains.