In a war-torn feudal Japan filled with mechs and magic, the greatest ronin knew, Yasuke, struggles to maintain a peaceful existence after a past life of violence. But when a local village becomes the center of social upheaval between warring daimyo, Yasuke must take up his sword and transport a mysterious child who is the target of dark forces and bloodthirsty warlords. A peaceful boatman once known as the Black Samurai is pulled back into conflict when he takes a little girl with mysterious powers under his wing.