An evil genius named Dr. Who creates Mechani-Kong, a robotic version of King Kong, to dig for a highly radioactive Element X, found only at the North Pole. Mechani-Kong enters an ice cave and begins to dig into a glacier, but the radiation destroys its brain circuits and the robot shuts down. Who then sets his sights on getting the real Kong to finish the job.
Kong manages to elude the evil Doctor and escapes by swimming all of the way to Japan where the climactic battle with Mechani-Kong transpires. Standing in for the Empire State Building from the original film is the Tokyo Tower where the two giants face off in the finale.