The 1963 American Version unfolds with United Nations reporter Eric Carter delivering critical news updates while monitoring various locations, including newsrooms in Chile. His reports highlight the unusual movement of icebergs from the Bering Sea and introduce a fascinating discovery made by a Japanese pharmaceutical company involving narcotic berries, which are protected by a colossal god. Intrigued by the potential of this monster god, Tako—the company’s advertising director—plots to capture the creature for promotional purposes.
In a further twist, Tako's colleague, Sakurai, meets with his sister and her boyfriend Fujita, who provides him with an ultra-strong wire intended for their adventurous expedition. Meanwhile, Carter tunes into the Seahawk, a UN submarine patrolling the Arctic. During its patrol, the submarine detects an iceberg that is strangely glowing. Following the captain's decision to submerge for investigation, the vessel collides with the iceberg and becomes ensnared. As the crew sends out a distress signal, a loud roar fills the air, leading to the arrival of a rescue helicopter. However, as they approach, the iceberg shatters and reveals Godzilla.
As chaos unfolds, Carter reports on Godzilla's assault on a military base. Frustrated by the creature's interference, Tako dispatches his team to Farou Island to retrieve a monster of their own. Upon arrival, Tako's men are captured by the local natives, who initially prohibit their presence. However, after offering some trinkets, the natives reluctantly allow them to stay. As the atmosphere grows tense with an impending thunderstorm, the villagers perform a musical ritual to appease their deity.
Inside the UN newsroom, Carter teams up with Dr. Arnold Johnson to analyze Godzilla's emergence. Johnson theorizes that electricity could potentially deter the monster. Meanwhile, as the expedition continues on Farou, the natives guide the explorers through the treacherous jungle. However, the tranquility is shattered when a piercing roar reverberates, startling the crew. With one crew member, Furue, falling ill, a young boy is sent to retrieve medicine derived from berry juice. But while he collects the potion, a giant octopus attacks, trapping the mother and child inside their hut. In a heroic turn of events, the island's god, King Kong, emerges to battle the octopus, successfully driving it back to the sea. After drinking the berry juice, Kong falls into a deep slumber, providing the explorers an opportunity to capture him and return to Japan.
This shocking event is broadcasted live, with Dr. Johnson suggesting that Kong may have a superior intellect to Godzilla, positing a fierce confrontation between the two monsters. However, Kong's journey to Japan is interrupted due to his perceived threat level. In Japan, military forces strategize to contain Godzilla as he rampages through the country, even attacking a train, endangering Sakurai's sister until her boyfriend rescues her. As the situation escalates, Tako is compelled to return Kong, but as they transport him, he breaks free, leaving them with no alternative but to attempt an explosive capture.
The inevitable clash occurs when Kong arrives in Japan to confront Godzilla. Spectators watch as their first battle unfolds, with Godzilla burning Kong before the latter chooses to flee in search of escape. The military’s efforts to trap Godzilla fail, leading to the establishment of an electrical blockade aimed at containing him. Yet, as Dr. Johnson warns, this might inadvertently strengthen Kong. The blockade manages to stall Godzilla, but Kong charges forth, wreaking havoc in Tokyo.
In a moment of desperation, Kong seizes Fujita's girlfriend and scales the Diet Building, just as the military plans an attack. However, Sakurai and Fujita intervene, concocting a scheme to induce sleep in Kong using the berry juice. The plan succeeds, freeing Sakurai’s sister while Kong dozes off. To ensure a definitive resolution, they devise a plan for Kong and Godzilla to square off, hoping the two titans will eliminate one another. Employing Fujita’s robust wire, they attach helium balloons to Kong, lifting him towards Mount Fuji.
As they reach their destination, Kong stirs just as Godzilla is spotted below. The two titans clash once more, with Godzilla initially overpowering Kong with his atomic breath. However, the onset of a storm infuses Kong with strength, allowing him to turn the tide. The battle rages on until both monsters tumble into the ocean, but only Kong rises to the surface. With a triumphant roar, Kong swims away as Carter concludes his report, bidding farewell to the legendary creature.
