At some point in the near future gun and weapon control laws are deregulated by public order. Because of this, Asia quickly becomes the epicenter of violent criminal activity in the world. In Yokohama City this violence becomes so extreme that the population quickly drops as ordinary people try to escape the criminal element that remain, leaving the northern part of the city as a haven of sorts to a particularly violent gang of four miscreants that call themselves The Jack Brothers. When The Jack Brothers viciously murder Milly's husband in daughter in front of her, leaving her to die, she vows revenge. She learns the art of sword combat from a master swordsman named Juubee, and eventually sets off to confront The Jack Brothers at their hideout in an abandoned factory.