Lex Barker first stepped into the loincloth of the Lord of the Jungle in . The story gets under way when Tarzan rescues a long-lost aviatrix named Gloria (Evelyn Ankers), who has been kept youthful by the magic fountain of the title. Bad guys Trask (Albert Dekker) and Dodd (Charles Drake) try to exploit the recuperative waters for mercenary purposes. They accompany the rapidly aging Gloria on an expedition back to the secluded valley where the magic waters flow. When the villains make their evil intentions known, Tarzan swings into action. Brenda Joyce plays Jane, just as she had in the last of the Johnny Weissmuller "Tarzan" entries. was co-scripted by horror-film vet Curt Siodmak.