A former legendary assassin known as the Crimson Devil, Ako Yamada, has left her bloody past behind to live as an ordinary teenage girl. She now works at the Piping Hot Bakery, doing her best to adjust to a peaceful life, though she is remarkably clumsy when it comes to everyday tasks after spending so many years in the underworld. Her new existence is threatened on two fronts. Nono Morino, a high school girl fascinated by urban legends, catches wind of a rumor that a hitman lives in the neighborhood and begins frequenting the bakery to investigate. At the same time, members of Ako’s former criminal organization, the notorious assassin syndicate Orochi, are also closing in on her.

The story is set in a contemporary Japanese town, revolving around the small bakery where Ako works and the surrounding residential area. The narrative follows the uneasy friendship and daily interactions between Ako, who is trying to hide her lethal skills and terrifying reputation, and the curious Nono. As Ako attempts to evade her former associates who are pursuing her, the story balances moments of violent action with slice-of-life comedy derived from Ako’s struggle to master mundane chores. The series explores themes of redemption and whether someone with a dark history can truly escape their past and find a peaceful, normal life.