Once upon a time, in the kingdom of Fortunia, a noble king and his lovely young queen lack but one blessing to make their joy complete. The queen gives birth to a daughter named Snow White, but dies soon after. The king mourns her, but in time, he remarries because of the pleading of his people. His new queen is a beautiful, but evil woman who soon becomes jealous of Snow White's beauty.

An American cowboy living in Mexico discovers his cattle is being eaten by a giant prehistoric dinosaur.

A massive underwater volcano erupts and puts a group of investigative scientists in danger. They are rescued by an atomic super submarine named The Alpha under the command of Captain McKenzie. The group is quickly taken to a vast underwater city known as Latitude Zero, a fantastic, Atlantean type utopia, a world beneath the ocean with its own sun. It is soon discovered that Captain McKenzie is at war with the evil Dr. Malic, a cruel scientist who wishes to rule mankind all the while conducting genetic experiments on humans and animals. Malic sends his agents to kidnap Dr. Okada, a human scientist who has created a serum that can immunize exposure to radiation.