Sawa was orphaned when her parents were brutally killed. She was then placed in custody by Akai and Kanie - detectives assigned to her case. These corrupt and immoral detectives train her to become a weapon by offering her the promise of revenge. Sawa becomes an assassin, targeting arbitrary individuals selected by her crooked overseers, including celebrities, politicians and influential businessmen. Sawa's weapon becomes infamous and she is known to the city's police officers. Akai physically abuses Sawa, causing her to dream of a life without her "guardians." One day, Sawa meets Oburi, a fellow orphan and vigilante. The two bond over their shared desperation and resentment towards an unjust world, dreaming of a future free from the burden of murder.