One Million B.C.

A group of modern hikers caught in a storm seeks shelter in a cave. They encounter an anthropologist interpreting prehistoric carvings that introduce the story of a young caveman.

Akhoba, the leader of the rock tribe, leads a hunting party. His son Tumak requests the right to his first kill, a small triceratops, which he wrestles to death. An older man in the group falls from a cliff and is left to die. The group reaches the rock tribe's cave with their prey. The animal is cooked over an open fire. When it is ready, the strongest eat first, then the women and children, and finally the few elders take the leftovers. Tumak defends his portion against Akhoba's demands. They fight, and Akhoba pushes Tumak off a cliff while his mother watches. Tumak recovers and finds a mastodon attacking him. He runs and climbs a tree. The mastodon rams the tree and pushes him