Two brothers, Takamaru and Kikumaru, are living with their father, Hakuraku-Ou, until one day Hakuraku-Ou is killed by "Death's-Head" Ginnosuke, a villain skilled in the art of sorcery. Hakuraku-Ou had long been seeking a Tiger Seal which, together with the Dragon Seal in his possession, would reveal the location of a huge ancestral fortune. But on the very night that the Tiger Seal was found, it was stolen by Tomomitsu, Ginnosuke's chief. When the two brothers receive the Dragon Seal from their father just before his death they determine to go to Death's-Head Castle, in order to recover the Tiger Seal.