The time is midst of samurai era when Ninja were banned. Sachi, a beautiful princess is traveling to Edo (present Tokyo) with her men including Denzo who is an ex-ninja whose true background has been hidden. Suddenly, they encounter an unidentified monster in a forest. As they battle to kill the monster, all of Sachi's men are killed except Denzo. Sachi starts to question his true identity and why Denzo risks his life to protect her.