Set in the Early Taisho era, Yuu, the daughter of a mistress belonging to the esteemed Toudou family, faced oppression and was treated like a servant from a young age. Notably, Yuu's half-sister Nadeshiko feigned kindness toward Yuu in front of Shinnosuke, the boy she admired, while secretly tormenting her. Yuu longed for freedom, yet her desire remained unfulfilled as she could not forsake her mother, who was locked away in a confinement room. One fateful day, a fire of mysterious origins claimed her mother's life, and though Yuu rushed to help her, she vanished without a trace. Fast forward seven years, Yuu, presumed lost, has transformed into a stunning young woman, adopting the name "Haruhi." She returns to the Toudou family, fueled by the memory of her slain mother, to exact her revenge.