Spurred on by the woman he loves, young journalist Edward Malone eagerly joins forces with irascible Professor Challenger on an expedition to South America. They are accompanied by Professor Summerlee, keen to expose his old rival as a fraud, and soldier-adventurer, Lord John Roxton. Their mission is to verify Challenger's claim of the existence of a mysterious Jurassic-age plateau untouched by human civilization that brings both wonder and terror in the form of prehistoric creatures, from fierce ape-men to grazing iguanodons and rookeries of pterodactyls.