Prehistoric times. A primitive man, returning from a fishing trip to his native cave, nearly becomes dinner for a giant crocodile just as a pack of predatory dinosaurs eats his wife and children. Soon, the orphaned man, to his own surprise, bands together with a Tyrannosaurus, who is unsuccessfully trying to defend his offspring from the same predators that killed his family. This will prove to be the beginning of an unusual friendship in a world where everything that moves either becomes your prey or tries to eat you.