12th century Japan: the country is in disarray when a strange star appears in the sky. At the gate of Gojoe Bridge, an invisible, demonic force has been attacking members of the Heike clan, violently beheading before they have a chance to defend themselves. A Buddhist monk, Benke, convinced that he's spiritually appointed to fight the evil force portended in the skies, arrives at the bridge, accompanied by the swordmaker Tetsukichi. Soon Benkei discovers that the demon is a man - Prince Shanao, who is seeking revenge on the Heike clan for ordering the death of his family. Hiding underneath Goje Bridge, Shanao has perfected his fighting skills and is ready to wreak the ultimate revenge.