Dr. Yamadano discovers the Fumoon, a newly evolved, intelligent humanoid species, on a small island after nuclear testing. They're initially dismissed as a hoax by most people, but a few witnesses like detective Shinsaku Ban, Rock, and Kenichi, who also has a sister named Pinoko, corroborate Dr. Yamadano's claims. The Fumoon are collecting animals worldwide, intending to evacuate Earth before an impending black gas cloud from a stellar explosion engulfs it, leaving mankind behind. One Fumoon, Rokoko, befriends Kenichi and helps Dr. Yamadano, Dr. Ochanomizu, and Dr. Frankenstein design a space ship for human evacuation.
