Jack was a prince from feudal-era Japan who wields an enchanted sword created by the gods to seal away the dark, shapeshifting demon known as Aku. His whole world came crumbling down when Aku reemerged and ravaged all he came in contact with. Jack was sent to travel the world and undergo training before returning to battle Aku. But before the prince could succeed, Aku created a time portal that sent the samurai into the hostile and lawless future that Earth has become under Aku's rule.