Cheeky, farcical and allegorical "true story" of the dawn of mankind. In the year 196303 BC, after a tribe of cavemen figures out how to have sex, O is born and, being different and more evolved than his xenophobic apeman and neanderthal family, immediately kicked out of their cave at birth. Young abandoned brontosaur Igua befriends him and takes care of him. While growing up, O befriends other dinosaurs as well, but once he realizes that he's not a dinosaur, he decides to find his own path in life and brakes off his friendship with Igua in a fit of anger. Igua wants to mend their friendship and decides to look for O until he finds him again. While roaming the prehistoric and even ice age world trying to survive on his own, O has many dangerous misadventures, becomes an inventor of fire and other important things, finds love with a somewhat humanoid feline creature in heat and eventually becomes a true renaissance man. During one of his misadventures, O stumbles upon his family again and, despite all, he's happy to see them. Unfortunately, when he tries to share his knowledge and progressive way of thinking with them, his primitive evil dumb brother Ah, who now leads the tribe, uses his teachings for mass destruction with the tribe's support. Throughout the movie, a soundtrack composed of rock songs tangentially related to the plot plays.