The Yagyu Ninja Scrolls: Revenge of the Hori Clan

17th-century Japan. A rebellion in the Aizu teritory has been brutally crushed, leaving twenty-one brave warriors dead
and most of the nuns of the local convent slaughtered. Now the surviving nuns have sworn to seek revenge.
They turn to the greatest swordsman of the land to train them to be able to kill the fiends who slew the men and the other nuns.