The Tokugawa Shogunate continues in power in 1931, the 64th year of the Meiji period. The government is guiding Japan into an advanced Edo era by monopolizing the newly found "Dragon Vein." During this period, an elite group of executioners known as the "Nue" is charged with defending the Shogunate from the "Kuchinawa," a rebel institution. Sawa Yukimura, the proprietor of Tsuyukasa Bookshop, conducts the store's day-to-day operations quietly. Behind the scenes, however, she is seeking vengeance on the man who massacred her tribe and family. Sawa, who has a particular power to morph due to her blue blood, joins Nue after being promised knowledge on the object of her vengeance: Janome, the leader of the Kuchinawa.