Ryota is sent by his mother to look for his missing brother, Yata, who has been lost a sea and given up for dead. Ryota meets Nita and Inchino, and convinces the two men take him to the boat docks several miles away. On a boat, they find another man, Yoshimura, who tells them they can stay overnight but must leave in the morning. In the morning, Ryota sails the boat out to sea hours before the others awaken. Listening to the radio, the three young men realize the older man is a thief who had robbed an export company of several million yen.
Days later they encounter strange cloud formations and a massive storm breaks out. The boat is tossed to and fro by the angry seas. The four are thrown overboard as a giant claw smashes the boat to pieces. They wash up on a remote island, and begin to explore their surroundings.
They spot a ship entering the bay, spewing a mysterious yellow gas. The ship docks at a fully equipped marina, and begins to unload it’s cargo, including several captives, apparently from nearby Pacific islands. Two of the captives find an outrigger canoe nearby and try to escape a secret military force. But they are intercepted and killed by Ebirah, a giant lobster-like creature, and the owner of the claw seen by the four men. A female captive slips away into the jungle and stumbles into the four men. The five barely escape being captured and enter a cave as a storm breaks out. The female captive, Dayo reveals she is from Infant Island, the home of Mothra, and that Yata is on the island. She tells the men many of the residents of Infant Island are being enslaved by the terrorist organization Red Bamboo, and Ebirah prevents their escape but Mothra is sleeping and cannot rescue them. The five later discover a sleeping Godzilla.
The five sneak into the Red Bamboo military compound. There, they find a fully equipped arsenal and make off with several smoke bombs. They also find out the Red Bamboo is making heavy water for the manufacture of nuclear weapons. The five are discovered by the terrorists’ security officer, but manage to escape using the smoke bombs. Outside the buildings one of the men, Nita, is captured, but Ryota escapes in an observation balloon.
Dayo, Yoshimura, and the other man return to the cave where Godzilla lies sleeping. Nita is thrown in with the captives from Infant Island, who are making the yellow liquid, which is sprayed from the Red Bamboo’s ships as an Ebirah-repellent.
Ryota floats to Infant Island and finds his brother. On the other island, they decide to shove a lightning rod into Godzilla in hopes of waking him to cover up their escape while the King of the Monsters hopefully destroys the heavy water plant. Nita convinces the captives to pour away the yellow liquid and make a fake batch. A fierce storm rolls in as Ryota and Yata approach the island after several days of rowing. Ebirah smashes their canoe, but they swim to shore.
The lightning from the storm shocks Godzilla awake. Godzilla, on the shore, and Ebirah, in the bay, volley a boulder back and forth several times before Ebirah tosses it nonchalantly into the island, smashing a guard tower. Godzilla and the giant lobster wrestle in the water for a time before Ebirah slinks away.
Dayo, Yoshimura, and the other man have been setting traps to aid their escape. As they begin setting more traps, Ryota and Yata are caught in one and need to be cut down. The five of them make their way to the Red Bamboo compound. As they consider plans to free the captives from Infant Island, they are spotted by the terrorists who chase them back into the jungle. They are all chased away by Godzilla. Dayo, however, gets left behind. Godzilla, though, seems intrigued with the beauty from Infant Island. Dayo tries to slip away as Godzilla naps, but a giant condor awakens Godzilla, who dispatches the condor with his nuclear breath. Suddenly, a group of Red Bamboo fighter jets attack the Godzilla, but he easily destroys them. Dayo is reunited with the others.
Hundreds of thousands of volts sent through high power lines manage to keep Godzilla from entering the compound. He kicks and stomps around the facility, and throws boulders inside, eventually causing the electricity to fail. The commander of the Red Bamboo orders the nuclear bomb to be set to self destruct. Several Red Bamboo soldiers retrieve the yellow liquid as they prepare to evacuate, not realizing it’s the bogus batch. Yoshimura uses his safecracking skills to free the captives, and they run past Godzilla who is continuing the smash the compound. A ship carrying the fleeing Red Bamboo leaves the harbor, spraying the bogus Ebirah-repellant. Ebirah just smashes the ship, killing all aboard. Godzilla heads to the harbor to finish his battle with the giant lobster.
Meanwhile, the now-freed captives are making a giant net and chanting to awaken Mothra as their friends on Infant Island perform a ceremonial dance in front of the giant moth. Mothra awakens as Godzilla and Ebirah continue their battle underwater. The timer on the nuclear bomb continues to tick away.
As Mothra flies to the island, Godzilla rips the claws off Ebirah, who swims away, likely mortally wounded. Mothra arrives and the captives gather into the net. Godzilla moves onshore and uses his nuclear breath. Mothra protects the escapees by beating her huge wings to create a giant wind, and then pushes Godzilla over. She picks up the net and they fly off. Because he helped them escape, the humans yell at Godzilla, urging him to run away. He leaps into the ocean moments before the nuclear bomb explodes.
The threat from the Red Bamboo, however, may not have been eliminated…
Human Cast: Akira Takarada (Yoshimura), Kumi Mizuno (Dayo), Akihiko Hirata (Captain Yamata), Jun Tazaki (Red Bamboo Commander)
Monster Cast: Godzilla, Ebirah, Mothra, Giant Condor
Notes: This was originally released in Japan as Godzilla vs. Ebirah, Horror of the Deep. There have been suggestions that this was originally to have been a King Kong movie, but Toho couldn’t secure the rights. There have been no further documented incidents involving the Red Bamboo terrorist organization. So far.
LogBook entry by Robert Parson