Lupin rescues a beautiful girl who has completely lost her memory. Learning that the key to her identity is in Persia, Lupin and company fly to Tehran, but through the machinations of Giranin's Red Spider Gang, who are after the girl, they end up being sentenced to beheading by the Iranian Army. The girl is in fact Ianne, daughter of Darius, king of ancient Persia. Will the "Eternal Rainbow," which only a hero may hold, disappear in a faraway whirlwind?