Dr. Nakazato (Chizuru Kitagawa) invents a chemical that makes a man invisible. Unfortunately the secret is leaked to a bad guy, and he kidnapps Dr. Nakazato and his assistant Kurokawa (Kanji Koshiba). While holding Dr. Nakazato as a hostage, the bad guy demands that Kurokawa become invisible and steal a famous diamond for him. Kurokawa then agrees to become an invisible man. Also stars Takiko Mizunoe and Daijirô Natsukawa. (In Japanese language).