Karyuu, a skilled shinobi working under the mysterious Aoi, grows weary of the cycle of assassination during an era of peace. After a failed attempt on the life of the formidable Ryuu, Karyuu's exceptional combat abilities and poise catch his attention. Intrigued by her strength, Ryuu offers her a new position, tempting her to leave her current life behind as the political tides begin to shift.
After surviving a poisoning attempt and being rescued by a mysterious man named Gisuke, the shinobi Kinoto finds herself caught in a power struggle between the vengeful Magoroku and his rival, Rihei. When confronted by the deadly assassin Karyuu, Kinoto refuses to fight and instead warns her that Magoroku is untrustworthy, urging the assassin to look beyond her orders to discover who her true enemy really is.
Aoi-sama assigns Shura and Hyakki to assist Karyuu in eliminating a dangerous opium merchant named Chen, but the mission is a ruse to monitor Karyuu's loyalty. After Karyuu confronts Chen and seeks information on a mysterious target, his companions reveal their true purpose. Accusing Karyuu of treason and spying for Gisuke, the two shinobi turn on their comrade, attempting to kill him because his superior strength has made him a threat.
Karyuu discovers she has been manipulated by Black Jyuuzou, the ruthless leader of assassins responsible for the massacre of her family. After a brutal confrontation with a vengeful survivor from her past and the tragic loss of Uzume, Karyuu is forced to confront the cruel cycle of the shinobi world. Devastated by these revelations, she decides to leave her old life behind and embark on a new journey with Kikka.