Under the cover of darkness, the elusive phantom thief Joker pulls daring heists on one expensive prize after another. Despite being driven into a hole by tenacious police investigator Dokusaburou Oniyama, the self-proclaimed "Miracle Maker" escapes using a slew of spectacular techniques that straddle the boundary between science and magic. Joker encounters Hachi, a clumsy but devoted ninja, in the middle of a robbery to steal the "Dragon Gem" from the estate of a snobbish multimillionaire. Hachi is chasing the same prize, but he idolizes Joker, who regards him as a nuisance in return. Nonetheless, the two are able to collaborate to pull off a successful theft. Joker was impressed by Hachi's humor and courage, as well as his practical ability to do housekeeping.