Rei is a female ninja and mother of a golden-haired daughter. During the time of the eighth Shogun, Yoshimune, Rei supports Yoshimune from behind the scenes, working with the priest Tenmu, a descendant of the monk Tenkai, to maintain peace in Edo. In September, when the Kanda Festival is held, news reaches Tenmu that Yoshimune has fallen. Taking advantage of the festival, someone has appeared who is plotting to assassinate Yoshimune. But there is a mastermind plotting this... What will happen?