A violent storm destroys an industrial park and washes a huge egg ashore in Japan. Reporter Sakai and his photographer, Junko, are taking pictures of the devastation when they find a strange organic object, which they give to Professor Miura, who has been called in to examine the giant egg.
The owner of the industrial park, an entrepreneur named Kumayama, buys the egg from the fishermen who retrieved it. He plans to build a huge incubator in his new amusement park, Happy Enterprises, where the egg will hatch.
But as Kumayama is making plans with his partner, Torahata, tiny twin women from Infant Island, the Shobijin, appear in their hotel room, begging the men to return Mothra’s egg to its island home. Instead, the two ruthless businessmen try to capture the Shobijin, who narrowly escape.
The Shobijin next seek out Sakai and Junko and beg them for help. The reporters try to assist, but appeals fall on deaf ears.
Professor Miura, meanwhile, has discovered that the organic object found at the industrial site is highly radioactive. He returns to the park and finds more evidences of radiation. Suddenly the ground quakes and Godzilla rises from the muddy soil.
As Godzilla goes on a rampage, the egg is endangered. The reporters fly to Infant Island and beg the Shobijin for help. The tiny women send Mothra, who battles Godzilla but is killed.
After the adult Mothra’s death, the egg hatches and two larvae emerge. These two wormlike creatures corner Godzilla and wrap him in a silk cocoon, dumping the mutant creature into the ocean.
Godzilla is defeated, and the Shobijin return with the Mothra larvae to their island home.
Monsters on Screen
モスラ（幼虫） Mothra Larva
Weapons in screen