This film focuses on Okatsu; the adopted daughter of a master swordsman. She is a master with a sword herself and her talents far overshadow that of her brother, and real child of the man who adopted her. Her brother unfortunately has a gambling habit, and it plunges the family into trouble when he loses a lot of money in a crooked dice game. After releasing he is unable to pay the debt he owes; the blame is shouldered by the father, who is killed, leading Okatsu on a path of revenge.