The film opens with Shiho Fujimura as a female assassin, seeking to kill her lord's mistress for what she sees as the good of her clan.
Attempting to deal with the guilt of his action, he becomes a monk and sends his son Shingo (Raizo Ichikawa) to be fostered by another family.
Not knowing much of his true past, Shingo sets out on a three-year journey at the age of 20 as a means of self-discovery.
At the end of his journey, he returns home with an incredibly defined and near unbeatable sword style and develops an intimidating presence.
He gains notoriety for his skills, but this spurs jealousy and betrayal and his foster family is wiped out by their neighbors.