Godzilla vs. Megalon

“Dreaded Megalon from the undersea kingdom! A miraculous deathblow from the wound-ridden Godzilla!”

Inventor Goro Ibuki (Katsuhiko Sasaki) builds a humanoid robot called Jet Jaguar, and for a while it is only his project. Then the Seatopians, an undersea people whose world has been wrecked by nuclear tests, take the robot and use it to guide their monster Megalon toward the surface. Jun Fukuda sends Goro, his young brother Rokuro (Hiroyuki Kawase), and their friend Hiroshi (Yutaka Hayashi) chasing after the machine he made.