The local villagers salvage it, and an entrepreneur of Happy Enterprises named Kumayama buys the egg from the local villagers. Instead of letting scientists study the egg, Kumayama wants to make it into a large tourist attraction.
While Sakai, Junko, and scientist Professor Miura are discussing the egg at a hotel, they discover Kumayama checking in. Kumayama meets with Jiro Torahata, the head of Happy Enterprises. They are unexpectedly confronted by two tiny twin girls known as the Shobijin and try to capture them. The Shobijin escape and meet with Sakai, Junko, and Professor Miura. After explaining that the egg belongs to Mothra and if the egg hatches, the larva will cause great damage, the trio agree to help.
Sakai, Junko, and Miura try to reason with Kumayama and Torahata but fail to do so and the Shobijin leave. Godzilla suddenly emerges from Kurada Beach, where it had been blown ashore by the hurricane and buried under mud, and begins to attack Nagoya. Sakai, Junko, and Miura travel to Infant Island to request the Shobijin to send Mothra to defeat Godzilla. The natives of the island and the Shobijin initially refuse but are eventually convinced by the trio.
Kumayama barges into Torahata’s room and demands to get his money back that Torahata had recently swindled from him. Kumayama is shot by Torahata and is too killed when Godzilla arrives and destroys his hotel. Mothra arrives just when Godzilla reaches her egg and engages him in battle. Despite giving her all, Godzilla defeats her and proceeds with his rampage.
The JSDF launch multiple campaigns against Godzilla until two giant larvas hatch from Mothra’s egg. They follow Godzilla to Iwa Island and trap him with their silk spray until he retreats back to the sea. Sakai, Junko, and Miura thank the Mothra larvas and Shobijin as they return to Infant island.