WHEN DINOSAURS RULED THE EARTH

The Cliff Tribe, led by Kingsor, are about to sacrifice three blonde women to their Sun God Akhoba, but one of the women, Sanna, escapes and is rescued by fishermen of the Seaside Tribe, among whom is Tara, who becomes enamoured with her.

Tara takes Sanna to his people, who also worship Akhoba, but without sacrifices. After building a hut for herself, she joins them at a celebration of a successful hunt, in which the men have captured a plesiosaur. The plesiosaur breaks free, but is subsequently killed and butchered. Ayak, a brunette woman who is jealous of Tara's feelings for Sanna, denounces Sanna as a witch and incites the elder women against her.

Kingsor and his men arrive, looking for Sanna. She flees, and hunters of her former tribe, led by Kane, give chase. During the search, the hunters are attacked by a Chasmosaurus, which gores Kane. When Tara seeks Sanna, the Chasmosaurus charges him and injures Khaku, one of his companions. He is chased to a cliff, where the Chasmosaurus loses its footing and plunges to its death. Khaku dies of his injuries shortly after, while Kane's wounds are tended to by the Seaside tribeswoman Ulido.

Khaku's funeral pyre at the shore is followed by a tribal frenzy during which an enraged Ayak burns down Sanna's hut. Sanna meanwhile becomes trapped by a carnivorous plant, and cuts off a portion of her hair in order to escape. As Tara goes looking for Sanna, he finds her hair trapped beneath the plant and assumes she is dead. Satisfied by this, Sanna's former tribe stop hunting her and join with Tara's tribe, with Kane, now healed, marrying Ulido.

Sanna seeks shelter in a Megalosaurus nest, fooling the mother and its baby into thinking she is one of them. Sanna grows attached to the baby and plays hide-and-seek with it, as well as teaching it to sit. Meanwhile, the overzealous Kingsor takes over the Seaside tribe and the womenfolk begin dyeing their blonde daughters' hair with tar in order to prevent them from being sacrificed like Sanna.

Some weeks later, Tara is carried off by a giant Rhamphorhynchus. After killing the pterosaur, he finds Sanna and her tamed dinosaur. The two are subsequently discovered and Tara is sacrificed to a Tylosaurus by Kingsor. Tara manages to escape and returns to Sanna.

The tribe then goes searching for Sanna again, and the two run away into a forest, where Sanna's dinosaur "parent" rescues her, but Tara is recaptured and the tribe prepare to burn him. The coastline, however, begins to recede, and the tribe is attacked by giant crabs. As a tsunami looms overhead, Sanna arrives to save Tara and they escape with Kane and Ulido aboard a raft. Kingsor tries to command the water to heal in a last effort to appease his deities, only to be swept away. While Ayak is running towards the raft, she steps into a trap of quicksand and is sucked down to her death. As the waters calm, the four survivors stop to witness a lunar eclipse, left in awe by the creation of the Moon above them.