When Jiro was an infant, a colossal oni brought him to his adoptive parents and promised to come back for him after 15 years. Now that the time has arrived, Jiro must face hostile oni, sinister cultists, and their servants while trying to shield his parents and girlfriend from their attacks. In the end, he must travel across time—past, future, and alternate dimensions—to accept his fate as the reincarnation of Shuten Doji.