Three years ago, a great fire broke out in Edo Castle, and the Shogunate lost its heir. A female swordsman, Yagyu Jubei Mitsugen, happens to meet Mitsugen, and with her overwhelming sword skills, she fends off one of the Sanada Mushiyuushi, Kakei Juzo, who attacks Mitsugen. In fact, the Mushiyuushi were responsible for the previous fire. Burning with revenge for the deaths of her sisters and subordinates, Mitsugen defeats the Mushiyuushi who are targeting Mitsugen.