Nishina Saburouta is powerful but corrupted priest. One night, an old samurai who couldn't bear him any more, attempts to kill him, but without success. Saburouta is rescued by his niece, Keisuke at the last moment. Keisuke is a a good-for-nothing. Since that event, he always turns to his uncle when he needs money. Recently Keisuke feels his uncle isn't as generous as he used to be, he suspects that Saburouta has found out the illicit relation between Keisuke and his uncle's young mistress, Ohasu.

In Edo-period Japan, Shingo is born the son of an assassin who was executed for murdering her lord’s concubine. Decades later, his adoptive family is massacred for keeping the secret. Armed with an unbeatable swordfighting technique, Shingo embarks on the path of the masterless samurai in search of vengeance and a path beyond his own ignominious origins.