After their boat is destroyed in the storm, the teenagers and thief, named Yoshimura, wash up on the shore of a mysterious island in the south seas. They soon discover that the island is home to a terrorist organization called the Red Bamboo, who has enslaved the local natives and is using them to harvest a rare mineral to build nuclear weapons.
While exploring the island, the group comes across a sleeping Godzilla, who has been trapped there by the Red Bamboo. Together with a beautiful native girl named Daiyo, who is part of a resistance group fighting against the Red Bamboo, the teenagers and Yoshimura hatch a plan to wake up Godzilla and use him to destroy the organization's nuclear weapon research facility.
After battling against the Red Bamboo's army of soldiers, including their giant lobster monster Ebirah, Godzilla is finally awakened and emerges from his slumber. He proceeds to wreak havoc on the island, destroying the Red Bamboo's base and freeing the enslaved natives.
With their mission accomplished and Godzilla returning to the depths of the ocean, the group and Daiyo bid farewell and leave the island, hoping to spread word of the cruelty and destruction caused by the Red Bamboo.