Young and adventurous reporter Edward Malone (Lloyd Hughes) is dispatched by his editor at the London Record Journal to cover a lecture by the boisterous Professor Challenger (Beery), who is convinced that dinosaurs are still roaming the earth. While the community thinks him a crackpot, he finds a believer in the esteemed hunter/explorer Sir John Roxton (Lewis Stone), who befriends Malone. Malone is introduced to Paula White (Bessie Love), whose father was left behind in the Amazon outback to contend with the mammoth creatures; it's the father's diary, featuring sketches of the dinosaurs, that's proof positive for Challenger of their existence.?Soon a rescue mission is under way and Paula, Malone, Challenger and Roxton are awestruck by the presence of brontosaurs, pterodactyls and allosaurs right before their eyes! The turbulent assaults of these prehistoric monsters, unexpected encounters and a frenzied volcano sequence make this a spellbinding cinematic experience that won't be forgotten. The spectacular animation effects by Willis O'Brien astonished audiences in 1925 and the plot which anticipates his later masterpiece, King Kong (a brontosaurus goes on a rampage through the streets of London), make this film an influential classic.