United Nations television reporter Eric Carter comments in a newscast on two items of unusual interest--first, mammoth icebergs are drifting toward Japan; second, scientists of the Pacific Pharmaceutical Company have discovered in the Solomon Islands some berries that produce a non-habit-forming narcotic. The scientists also find King Kong, who mysteriously appears during an electrical storm and kills a giant octopus. To boost a current advertising campaign, the company sends two men to capture the beast by drugging him with the narcotic. Meanwhile, the prehistoric monster Godzilla emerges from an iceberg in the Arctic Ocean, destroys a nuclear submarine, and heads toward Japan. King Kong awakens in captivity, senses the approaching enemy, and escapes from his captors. Nothing can stop the two creatures as they trample everything in their paths. They finally meet in combat atop Mount Fuji, and their battle creates an earthquake, sending them over a high cliff into the sea. Godzilla disappears, and King Kong moves on south.