Inscribed Photo to
Doyle From a lost expedition to a plateau in the borders of
Peru,
Brazil and
Colombia, Paula White brings the journal of her father, explorer Maple White, to the eccentric Professor Challenger in
London. The journal features sketches of
dinosaurs which is enough proof for Challenger to publicly announce that dinosaurs still walk the earth. Met with ridicule at an academic meeting at the Zoological Hall, Challenger reluctantly accepts a newspaper's offer to finance a mission to rescue Maple White. Professor Challenger, Paula White, sportsman Sir John Roxton, news reporter Edward Malone (who is a friend of Roxton and wishes to go on the expedition to impress his fiancée), a skeptical professor Summerlee, an Indian servant Zambo, and Challenger's butler Austin leave for the plateau. At their campsite at the base of the plateau, the explorers are shocked when a large rock falls, sent their way by an
Apeman perched on top of an overhead ledge. As the crew look up to see their attacker, Challenger spies overhead a
Pteranodon eating a young
Toxodon which proves that the statements in Maple White's diary are true. Leaving Zambo and Austin at the camp, they cross a chasm onto the plateau by cutting down a tree and using it as a bridge, but it is knocked over by a
Brontosaurus, leaving them trapped. The explorers witness various life-and-death struggles between the prehistoric beasts of the plateau. An
Allosaurus attacks an
Trachodon, and knocks it into a bog. The
Allosaurus then attacks, and is driven off by a
Triceratops. Eventually, the
Allosaurus makes its way to the campsite and attacks the exploration party. It is finally driven off by Ed who tosses a torch into its mouth. Convinced that the camp is not safe, Ed climbs a tree to look for a new location, but is attacked by the apeman. Roxton succeeds in shooting the apeman, but the creature is merely wounded and escapes before he can finish him off. Meanwhile, an
Agathaumas is attacked by the
Allosaurus, and gores it to death. Suddenly, a
Tyrannosaurus attacks and kills the
Agathaumas, along with an unfortunate
Pteranodon. The explorers then make preparations to live on the plateau potentially indefinitely. Challenger designs a catapult to defend the camp. During a search for Maple White, Roxton finds his remains, confirming his death. It is at this time that Ed confesses his love for Paula and the two declare their intention to be wed by Summerlee who used to be a minister. Shortly afterwards, as the paleontologists are observing the
Brontosaurus, a
Tyrannosaurus attacks it, and the
Brontosaurus falls off the edge of the plateau, becoming trapped in a mud bank at the base of the plateau. Soon afterwards, a volcano erupts causing a mass stampede among the giant creatures of the lost world. The crew is saved when Paula's pet
monkey Jocko climbs up the plateau carrying a rope. The crew use the rope to pull up a rope ladder constructed by Zambo and Austin and then climb down. As Ed makes his descent, he is again attacked by the apeman who pulls the rope ladder. The apeman is again shot and finally killed by Roxton. They discover the
Brontosaurus that had been pushed off the plateau had landed softly in the mud of the river, trapped but still alive, and Challenger manages to bring it back to London, as he wants to put it on display as proof of his story. However, while being unloaded from the ship, the spooked and disoriented animal escapes and causes havoc until it reaches Tower Bridge, where its massive weight causes a collapse, and it swims down the River Thames. Challenger is morose as the creature leaves. Ed discovers that the love he left in London has married in his absence, allowing him and Paula to be together. Roxton morosely but gallantly hides his love for Paula as Paula and Ed leave together, while two passersby note: "That's Sir John Roxton – sportsman." ==Cast==