Explorer Professor Challenger is taking quite a beating in the London press thanks to his claim that living dinosaurs exist in the far reaches of the Amazon. Newspaper reporter Edward Malone learns that this claim originates from a diary given to him by fellow explorer Maple White’s daughter, Paula. Malone’s paper funds an expedition to rescue Maple White, who has been marooned at the top of a high plateau. Joined by renowned hunter John Roxton, and others, the group goes to South America, where they do indeed find a plateau inhabited by pre-historic creatures, one of which they even manage to bring back to London with them.
Adventure | Fantasy | Horror | Sci-Fi
| Bessie Love | … | Miss Paula White (as Miss Bessie Love) | |
| Lewis Stone | … | Sir John Roxton (as Mr. Lewis Stone) | |
| Wallace Beery | … | Prof. Challenger (as Mr. Wallace Beery) | |
| Lloyd Hughes | … | Edward E. Malone (as Mr. Lloyd Hughes) | |
| Alma Bennett | … | Gladys Hungerford (as Miss Alma Bennett) | |
| Arthur Hoyt | … | Prof. Summerlee (as Mr. Arthur Hoyt) |