Based on the famous Arthur Conan Doyle book, starring Wallace Beery with Bessie Love and Lloyd Hughes starts with Professor Challenger facing a skeptical press corps when he asserts that giant dinosaurs are alive and flourishing in the farthest depths of the Amazon. Newspaper reporter Edward Malone learns that this claim originates from a diary given to the professor 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, the group goes to South America, where they do indeed find a plateau inhabited by prehistoric creatures.
