Professor Challenger, on an expedition to South America, shoots an animal that he claims is a pre-historic pterosaur. On his return to England, his fellow Professor, Summerlee, and most of the scientific establishment dismiss it as a hoax. However, an ambitious hunter and womaniser John Roxton and journalist Edward Malone are prepared to undertake the mission to find the truth. Challenger, Summerlee, Roxton and Malone set off for a Brazilian plateau in search of pre-historic life.