In a Japan still under the Tokugawa Shogunate's rule during the Meiji era's 64th year, the discovery of the potent 'Dragon Vein' propels the nation toward progress in the Edo period. Amidst this backdrop, a covert group of enforcers called 'Nue' safeguards the Shogunate against the rebellious 'Kuchinawa.' Sawa Yukimura, the unassuming owner of Tsuyukasa Bookshop, harbors a deep-seated thirst for retribution against the individual responsible for annihilating her kin. Endowed with a unique power from her royal lineage, Sawa enlists in Nue's ranks enticed by the promise of vital intelligence regarding her sworn enemy: Janome, the mastermind behind Kuchinawa.