Inventor Goro Ibuki creates a humanoid robot named Jet Jaguar. It is soon seized by an undersea race of people called the Seatopians. Using Jet Jaguar as a guide, the Seatopians send Megalon as vengeance for the nuclear tests that have devastated their society.
Starring Katsuhiko Sasaki, Yutaka Hayashi, Hiroyuki Kawase, Kanta Mori, Kotaro Tomita, Ulf Otsuki, Sakyo Mikami, Fumiyo Ikeda, Robert Dunham, Gentaro Nakajima