In order to flee from powerful enemies, young Mayan king Balam leads his people north across the Gulf of Mexico to the coast of what will become the United States. They build a home in the new land but come into conflict with a tribe of Native Americans led by their chief, Black Eagle, while both Balam and Black Eagle fall in love the beautiful Mayan princess Ixchel.

When Dinosaurs Ruled the Earth is a movie starring Victoria Vetri, set in the time of cavemen. The film was made by Britain's Hammer Films. Like several of Hammer's previous films, such as One Million Years B.C. (1966), the film portrays dinosaurs and humans alongside each other. Directed and scripted by Val Guest, it was based on a treatment by J.G. Ballard, and nominated for an Oscar for its visual effects.