Rose, who became an assassin to survive as an immigrant, is in a romantic relationship with her local schoolgirl girlfriend, Kōka. However, Kōka has given up on revealing their relationship to her father, who would never accept it. Unbeknownst to them, Kōka's father is the priest of the church that Rose attends, and he is the one to whom Rose confesses her sins of murder. Meanwhile, the "organization" that employs Rose is also starting to move, complicating the web of relationships in her life beyond imagination!?!