Chief Akhoba (Robert Brown) leads a hunting party into the hills. They trap a giant warthog in a pit and Akhoba’s son Tumak (John Richardson) kills it. When they bring it home for dinner, Tumak and Akhoba fight over it and Tumak is banished to the desert. After escaping a giant iguana, some ape men, a brontosaurus, and a giant spider, he collapses on the beach. He is found by Loana, the Fair One (Raquel Welch), one of the handsome blond Shell Tribe. A giant turtle called an Archelon appears on the beach and is driven into the sea. Tumak is taken to the village and Loana tends to him. The Shell People have cave paintings, music, jewelry, and language. Tumak has never encountered such things before.

An Allosaurus attacks the women fishing and they flee, leaving a young girl behind. Tumak grabs a spear from Ahot (Jean Wladon) and uses it to defend the girl as Loana hustles her away. One of the men who come to Tumak’s aid is killed and there is a funeral. Tumak takes the spear which he used against the Allosaurus, his right according to his tribe, and has to fight Ahot. Tumak is kicked out and Loana leaves with him.

Back in Tumak’s tribe, his brother Sakana (Percy Herbert) overthrows Akhoba, who is injured. Tumak and Loana come upon a battle between a Ceratosaurus and a Triceratops, which wins. Loana meets the Rock Tribe, but there are fights, notably between Loana and Tumak’s ex, Nupondi the Wild One (Martine Beswick). Loana wins the fight but declines to kill Nupondi. Sakara doesn’t hold with the Shell People’s nonviolent ways.

Loana teaches them how to swim. They are attacked by a Pteranodon. Loana is snatched but dropped into the sea. She struggles to shore during a Pteranodon versus Rhamphorhynchus battle. Tumak assumes she has been eaten. Sakara rebels against Akhoba. Tumak, Ahot, and the returned Loana, plus other Shell People, join the fight against Sakana. During the battle, a volcano erupts, and the tribes are overwhelmed with earthquakes and landslides. The survivors set out to find a new home.

Exterior filming took place on Lanzarote and Tenerife in the Canary Islands. The volcanic eruption and lava flows were made of wallpaper paste, oatmeal, dry ice, and red dye. The dinosaurs were filmed in Harryhausen’s studio in London. Some dinosaur scenes were similar to those in the original film, 1940’s Hammer Production One Million B.C. Robert Brown wears makeup similar to Lon Chaney Jr. in that film. Some of the dinosaurs were used later in Valley of Gwangi. Some scenes, mostly gruesome, were cut by American censors, and though a dance by Martine Beswick was cut, Raquel Welch was not. The fur bikinis, which were soaking wet much of the time, were extremely heavy.

It has often been said that there were two great engineering marvels in the movie—Ray Harryhausen’s dinosaurs and Raquel Welch’s costume, which was made by costume designer Carl Toms by covering Welch with doeskin and cutting parts way. There is no Oscar for Outstanding Achievement in Mammalian Containment (call it the Howard Hughes/Jane Russell Award) but the poster of her became the great pinup of the Sixties. Martine Beswick and Raquel Welch did their own stunts. Beswick was a Bond Girl in From Russia with Love and Thunderball. John Richardson married her and not Raquel Welch. They were together for Seven Years. She appeared later in Prehistoric Women. The movie was mentioned in the trailer for A Nymphoid Barbarian in Dinosaur Hell (1990).