Through the ample use of stock footage (about ten minutes!) it's explained that a new planet has attached itself to our solar system and is within rocketship distance from Earth. The scientists name this planet NOVA. A bunch of scientists, two men and two women, are sent to investigate and come across a landscape that looks remarkably like their world. They're unfazed that there's deer, woolly mammoths and black bears (footage from the original ONE MILLIONS YEARS B.C), but refer to them as primitive life forms. They eventually decide to explore a mysterious looking island and come across lizards made up to look like dinosaurs. When we see the giant iguana with the horn glued to its snout one of the scientists exclaims 'That looks just like Tyrannosaurus Rex'.! Maybe he was getting it confused with the American version of Godzilla...Anyway, the King Dinosaur traps them in a cave and they have to get away. A giant alligator comes along and the two beasts battle. They eventually escape its lizard clutches and blow the island up in an atomic explosion. At this point they realize they should probably head back home.