 A fisherman named Yata winds up missing after the boat he is working on sinks. His younger brother Ryota decides to search for him, but when the authorities refuse to help him he tries to enter a dance contest to win a boat to go search for Yata. When Ryota arrives at the contest he finds out he is too late by a few days, but meets up with two contestants who had already been eliminated named Nita and Ichino. The three youths then head for the marina to look at different boats. After they board one, they meet a rifle toting man named Yoshimura, whom they assume is the owner. However, he is a bank robber who is using the boat to hide out. After a few minutes, Yoshimura decides to let the youths stay the night. The next morning they wake up to find out that Ryota has set sail with them on it to search for his brother. A few days into their trip they are caught in a storm and as the boys try to keep the boat from sinking they see a giant claw emerge from the water. The next morning they wake up on Lechti Island, which serves as the base for a group of international terrorists called Red Bamboo, who have a heavy water factory on the island. They also observe as a boat belonging to the group arrive with slaves from Infant Island, the home of Mothra. Some of the natives try to make a break for it, but they are caught and eaten by the same monster that wrecked the boys boat, a giant lobster named Ebirah. During the commotion, a slave girl named Daiyo manages to sneak away and runs into the boys. They then find a cave where they hide out. But also in the cave is Godzilla, who is hibernating. They then try to head for the base to see if they can save the slaves, but their plans are thwarted and Ichino becomes a prisoner while Ryota gets caught in an observation balloon and drifts towards Infant Island where he is reunited with Yata. In the meantime, Nita gets an idea to awaken Godzilla with lightning to not only distract the soldiers but to fight Ebirah.