| Director | Ishirō Honda |
|---|---|
| Budget | ¥60 million |
| Box office | $2.2 million |
In 1954, after the Japanese freighter Eiko-maru is destroyed near Odo Island, another ship—the Bingo-maru—is sent to investigate, only to meet the same fate with few survivors. A fishing boat from Odo is also destroyed, with one survivor. Fishing catches mysteriously drop to zero, blamed by an elder on the ancient sea creature known as "Godzilla". Reporters arrive on Odo Island to further investigate. A villager tells one of the reporters that something in the sea is ruining the fishing. That evening, a storm strikes the island, destroying the reporters' helicopter, and Godzilla, briefly seen, destroys 17 homes, kills nine people, and kills 20 of the villagers' livestock.
Odo residents travel to Tokyo to demand disaster relief. The villagers' and reporters' evidence describes damage consistent with something large crushing the village. The government sends paleontologist Kyohei Yamane to investigate the island, where giant radioactive footprints and a trilobite are discovered. The village alarm bell is rung, and Yamane and the villagers rush to see the monster, retreating after seeing it is a giant dinosaur. Yamane presents his findings in Tokyo, estimating that Godzilla is tall and has evolved from an ancient sea creature, becoming a terrestrial creature. He concludes that Godzilla has been disturbed by underwater hydrogen bomb testing. Debate ensues about notifying the public about the danger of the monster. Meanwhile, 17 ships are lost at sea.
Ten frigates are dispatched to attempt to kill the monster using depth charges. The mission disappoints Yamane, who wants Godzilla to be studied. When Godzilla survives the attack, officials appeal to Yamane for ideas on how to kill the monster. Still, Yamane tells them that Godzilla is unkillable, having survived H-bomb testing, and that it must be studied. Yamane's daughter, Emiko, decides to break off her arranged engagement to Yamane's colleague, Daisuke Serizawa, because of her love for Hideto Ogata, a salvage ship captain. When a reporter arrives and asks to interview Serizawa, Emiko escorts the reporter to Serizawa's home. After Serizawa refuses to divulge his current work to the reporter, he gives Emiko a demonstration of his recent project on the condition that she must keep it a secret. The demonstration horrifies her, and she leaves without mentioning the engagement. Shortly after she returns home, Godzilla surfaces from Tokyo Bay and attacks Shinagawa. After attacking a passing train, Godzilla returns to the ocean.
After consulting international experts, the Japan Self-Defense Forces constructs a tall and 50,000 volt electrified fence along the coast and deploys forces to kill Godzilla. Dismayed that there is no plan to study Godzilla for its resistance to radiation, Yamane returns home, where Emiko and Ogata await, hoping to get his consent for them to wed. When Ogata disagrees with Yamane, arguing that Godzilla's threat outweighs any potential benefits from studying the monster, Yamane tells him to leave. Godzilla resurfaces and breaks through the fence to Tokyo with its atomic breath, unleashing more destruction across the city. Further attempts to kill the monster with tanks and fighter jets fail, and Godzilla returns to the ocean. The day after, hospitals and shelters are crowded with the maimed and the dead, with some survivors suffering from radiation sickness.
Distraught by the devastation, Emiko tells Ogata about Serizawa's research, a weapon called the "Oxygen Destroyer", which disintegrates oxygen atoms and causes organisms to asphyxiate, then dissolve, leaving nothing behind. Emiko and Ogata go to Serizawa to convince him to use the Oxygen Destroyer. Still, he initially refuses, explaining that if he uses the device, the world's superpowers will force him to construct more Oxygen Destroyers as a superweapon. After watching a program displaying the nation's current tragedy, Serizawa finally accepts their pleas. As Serizawa burns his notes, Emiko breaks down crying.
A navy ship takes Ogata and Serizawa to plant the device in Tokyo Bay. After finding Godzilla, Serizawa activates the device and cuts off his air supply, taking the secret of the Oxygen Destroyer to his grave. The Oxygen Destroyer successfully kills Godzilla and disintegrates its body; many mourn Serizawa's death. Yamane believes that if nuclear weapons testing continues, another Godzilla may rise in the future.