One evening, young Mikko Mura receives a telephone call from an unknown man identifying himself as a messenger of Rodak, a conqueror from outer space. The caller tells Mikko that Rodak will take the boy on an interesting journey.
Goldar takes Mikko to his base, in the heart of the active volcano Mt. Olympian. There Mikko meets Goldar's wife Silvar, and Mathusam, an elderly, scientist. They are taken with Mikko and ask Mathusam to create a son for them in his image.
Rodak's creature is a mole-like animal that can move under the earth. As strange earthquakes begin to take place all over, Rodak announces his plans to conquer the Earth and asks that the people surrender their planet peacefully.
Molesaurus is found to be carrying an H-Bomb in its body, planted there by Rodak. Rodak appears again and demands that the people of Earth surrender or he will blow up the entire planet with an army of monsters like Molesaurus.
Tom with Kita, another reporter, investigate the whereabouts of the flying saucer and turns out to be a small glowing mechanism that appears to be breathing. It increasing mass, the object changes into a new creature of Rodak's: Birdaurus.
Birdaurus attacks an atomic power plant and begins to destroy it. Goldar arrives to stop the creature. While Rodak attempts to gain Gam and Mikko confidence and tells them that on his ship, children only play all day long.
Goldar attacks Birdaurus at the atomic power plant, but is tricked by the creature and drained of his power. Mikko gets Lily, one of the children on Rodak's ship, to help him release Gam and all three return to Earth.
Gam believes that Lily is an agent of Rodak but Mikko disagrees. It's really one of the Lugo Men disguised as Rita. Goldar, now fully recovered, comes to battle Birdaurus while Tom Mura and the real Kita escape from Rodak's saucer.
Tomoko is captured then replaced by a Lugo Man but Mikko and Tom discover Tomoko is an imposter he turns back then disappears through a wall. While Rodak's latest monster Zandosis is draining all the sound waves from the air.
