Tokugawa Ieyasu is the ruler of all Japan. But one last loose thread must be tied up before his domination is complete -- the destruction of the Toyotomi clan, now beseiged in Osaka castle. Ieyasu's ninja are the only ones who can penetrate the fortress, but unfortunately for Ieyasu, Kirigakure Saizo (Ichikawa) and the other Toyotomi ninja can just as easily get out. As armies of samurai maneuver for battle, the fate of the nation will be decided by a desperate struggle in the dark!