Invasion of the Astro-Monsters

When astronauts Fuji and Glen investigate the newly discovered Planet X, they encounter a race of super-intelligent beings who need Earth's help. Ghidra, the three-headed monster, is destroying the mysterious planet. Only Godzilla and Rodan can stop Ghidra, so the people of Planet X want to transport Earth's monsters to their world. The astronauts agree to the plan--but the leaders of Planet X take control of the creatures and use them as weapons to conquer planet Earth! As the aliens and their monsters storm the Earth with a campaign of destruction, military forces struggle to defend the helpless victims while scientists race to discover the aliens' weakness. (official distributor synopsis)