The first Godzilla (Gojira) film that began a legacy and it all started when a Japanese fishing boat is destroyed near Odo Island, another ship is sent to investigate only to meet the same fate with few survivors. Reporters arrive on Odo Island to further investigate. A village elder tells one of the reporters that he believes the poor fishing and ship disasters are being caused by an ancient sea creature known as “Godzilla”. That same night, an unseen force comes ashore during a storm and attacks the village.
Palaeontologist Kyohei Yamane leads an investigation crew to the island, where giant radioactive footprints and a trilobite are discovered. An alarm rings and Dr. Yamane and the villagers encounter Godzilla up a hill. Dr. Yamane returns to Tokyo to present his findings and concludes that Godzilla was resurrected by repeated nuclear tests. Ships are sent with depth charges to kill the monster. However, Godzilla appears to have survived and causes nationwide panic. Officials appeal to Dr. Yamane for ideas to kill the monster, but Yamane wants him kept alive and studied.
Dr. 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. However, Dr. Serizawa gives her a demonstration of his recent project which horrifies her and is sworn to secrecy while unable to break off the engagement. That night Godzilla surfaces from Tokyo Bay and attacks the city. The next morning, the JSDF construct a line of tall electrical towers along the coast of Tokyo. Godzilla resurfaces and breaks through the electrical fences, proceeding with his rampage across Tokyo.
Distraught by the devastation, Emiko tells Ogata about Dr. Serizawa’s Oxygen Destroyer, which disintegrates oxygen atoms and the organisms die of a rotting asphyxiation. Emiko and Ogata go to Dr. Serizawa to convince him to use the Oxygen Destroyer but he initially refuses. After watching a program displaying the nation’s current tragedy, Dr. Serizawa finally gives in to Emiko and Ogata’s pleas.
A navy ship takes Ogata and Dr. Serizawa to plant the device in Tokyo Bay. After finding Godzilla, Dr. Serizawa unloads the device and cuts off his air support, taking the secrets of the Oxygen Destroyer to his death. The mission proves to be a success but many mourn at the unexpected loss of Dr. Serizawa. Dr. Yamane believes if nuclear tests continue, another Godzilla may rise in the future.