Retired from ninja duty, Torakage lives a peaceful life in a small village with his wife and son. One day, Torakage's son is kidnapped by his former mastress in an attempt to force him to break into a nearby castle and steal the Gold Scroll, the counterpart to her Silver Scroll, the two of which when brought together point the way to a vast treasure. Having no choice, Torakage and his wife sneak into the castle. However, their plan goes awry and the two are caught and turned over to the evil lord. Now, with his wife a hostage of the lord, Torakage must bring him the Silver Scroll held by his former mastress or forfeit her life! Utilizing weaponry crafted by an eccentric inventor, Torakage takes on both sides and plays them and their ninja armies off each other in the hope of saving his family.