Major Ben McBride organises a mission to the Antarctic wastes to search for his friend Bowen Tyler who has been missing in the region for several years. A British naval survey ship takes them to Caprona. McBride's party: the paleontologist Norfolk, gunner and mechanic Hogan and photographer Lady Charlotte 'Charlie' Cunningham fly over the mountain wall of Caprona in an amphibious aircraft, but are attacked by a pterodactyl and forced down. They find themselves in a world populated by primitive warriors and terrifying prehistoric creatures, all of whom they must evade in order to get back safely to their ship. They meet a cave-girl, Ajor, who can speak English ; she leads them to the land of a race of samurai-like warriors called the Nargas, who are keeping Tyler prisoner. When the volcano that the Nargas worship erupts, they must escape the cataclysm engulfing the land. Tyler sacrifices himself to cover their retreat.
According to Kevin Connor, Amicus Productions wanted to follow At the Earth's Core with an adaptation of the John Carter of Mars stories, but could not afford the rights, so they made this sequel instead. Although the film was made by Amicus Productions, the company folded before it was released, meaning AIP took sole credit.
Changes
The film makes some notable changes from the book:
The lost world is a "polar continent" rather than the interior of a polar island.
Bowen dies in the film and Lisa is already dead during the events of the film, while they both survive in the novel.
In the book, the ship's crew scale the mountains to come to the rescue.
Time Out thought the film "A lame sequel to Connor's earlier Edgar Rice Burroughs adaptation, The Land That Time Forgot, which was at least occasionally lively"; the Radio Times called it an "OK sequel," but a "constipated confection" with "ludicrous mechanised dinosaurs and hopeless acting from an interesting cast." The reviewer however, found that "A few shots, composed around celebrated fantasy illustrations, compensate for all the film's shortcomings"; and critic Derek Winnert similarly opined "the monsters and special effects are below par," but "there are effective moments, and there is some curiosity value in seeing singer Dana Gillespie playing Ajor"; while Blu-ray.com thought the film "may not be the most polished effort around, but there's fun to be had with its crazy dino encounters."
