Akoba (Robert Brown (British actor)) leads a hunting party into the hills to search for prey. One member of the tribe traps a warthog in a pit, and then Akoba's son Tumak (John Richardson (actor)) kills it. The tribe brings it home for dinner and Tumak is later banished to the harsh desert because of a fight over a piece of meat with Akoba. After surviving many dangers such as a giant iguana, Hominidae, ''Brontosaurus'' and a giant spider, he collapses on a remote beach, where he is spotted by "Loana the Fair One" (Raquel Welch) and her fellow fisher-women of the Shell tribe. They are about to help him when an ''Archelon'' (which is three times the size of the actual Prehistory Archelon) makes its way to the beach. Men of the Shell tribe arrive and drive it back into the sea. Tumak is taken to their village, where Loana tends to him. Scenes follow emphasising that the Shell tribe is more advanced and more civilized than the Rock tribe. They have cave paintings, music, delicate jewelry made from shells, agriculture, and rudimentary language;– all things Tumak seems to have never before encountered.