Professor Davidson and his daughter Diana 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, and Dr. Max Bremmer, a Nazi agent who plans to destroy the native tribes' livelihood to build a secret German air base at Zoloz. But Diana's fiancé Godfrey Prescott is The Phantom, feared and respected by the natives, who circumvents the traps and schemes of the villains.
