Invasion of Astro-Monster 1965

1966. On a mission for the UN, astronauts Glen and Fuji set out to explore Planet X. The local humanoids tell the astronauts that they are forced to live underground due to constant attacks by the terrifying Monster Zero. During yet another attack, the astronauts recognize the monster as King Ghidorah. Responding to a request for help, Godzilla and Rodan are transported from Earth to Planet X, where they triumphantly defeat the monster. Everything would be fine, but in reality, the natives of Planet X needed Godzilla and Rodan for an entirely different purpose...