When master thief Lupin III (Yasuo Yamada) discovers that the money he robbed from a casino is counterfeit, he goes to Cagliostro, rumored to be the source of the forgery. There he discovers a beautiful princess, Clarisse (Sumi Shimamoto), who is being forced to marry the count so he can find the legendary treasure of Cagliostro. In order to rescue Clarisse and foil the count, Lupin teams up with his regular adversary, Inspector Zenigata, as well as fellow thief Fujiko Mine.