Taisho Junai Fukushuutan - Haha wo Yaki Korosareta Watashi wa Oni to Kasu

Yuu is the child of a concubine from the prominent Todo family, and she experiences mistreatment akin to that of a slave from a very young age. Notably, her half-sister Nadeshiko acts friendly towards Yuu in the presence of Shinnosuke, whom she admires, but she relentlessly bullies Yuu when no one is watching. Yuu had dreamed of escaping her situation, but she could never leave her mother, who was imprisoned in a dungeon. One day, an unidentified fire claims her mother's life, and Yuu, who had gone to rescue her, also vanishes.

Seven years later, Yuu, believed to be lost, has transformed into a stunning young woman, as if she were an entirely different person. She adopts the name Haruhi, returns to the Todo family, and embarks on a mission to exact revenge for her mother's untimely death.