The protagonist, Ogawa Mezame, possesses the unique ability to perceive his world as a video game, having previously used this knowledge to his advantage. One night, he encounters Akari, a girl sitting alone on the street. Mezame recognizes her from a game as a potential heroine but is troubled by her current situation, as she claims to have no surname and has been kicked out of her home. He offers her shelter, proposing a debt where she repays him with something other than money, implying a physical repayment. Akari, initially shocked, eventually accepts his offer, desperate for a place to stay.
Mezame brings Akari to his spacious, self-designed house. He buys her clothes and groceries, noting her potential to be a big eater, a trait from her game persona. Akari bathes, reflecting on her past. She was adopted by a Shinto family at age five and trained as a shrine maiden to exorcise monsters. She excelled, but her life changed when a boy with even greater talent was taken in. Akari and other girls were gathered to bear children with him, but only one would be chosen. Akari was not selected, and instead of being returned home, she was deemed worthless and intended to be a sacrifice. She fled, eventually ending up on the street where Mezame found her. She decides to repay Mezame with her body, seeing his offer as a form of kindness she hadn't experienced.
Mezame, aware of Akari's intended fate as a sacrifice in the game, plans to protect her. He arranges for her to have a new identity, "Shinohara Akari," and enrolls her in his school. Akari quickly becomes popular due to her cuteness, though she struggles with modern trends and her past trauma. Mezame, while seemingly detached, is actively manipulating events to keep Akari safe and under his protection, even using his considerable influence and wealth to pressure the Shinto family.
During a ritual to sacrifice Akari, Mezame intervenes with the help of his connections, including Akagi Renya, the chairman of a major corporation that invests in the Shinto family. Mezame reveals his significant stake in the company and uses the Shinto family's mistreatment of him and Akari's situation to force them to relinquish Akari's custody. He also uncovers that Akari has a mild mental illness, further solidifying his claim to protect her. The Shinto family, unable to prove their guardianship and facing financial repercussions, is forced to agree.
Mezame brings Akari back to his home, where their relationship intensifies. Akari expresses deep gratitude, and their physical intimacy becomes more frequent. Later, Akari's friend, Shindo Aona, another girl who competed for the boy in the game, arrives seeking protection from Mezame, indicating a potential new development in Mezame's habit of "picking up" discarded heroines. The story concludes with Mezame reviewing documents from the Shinto family, hinting at further complexities and potential world-changing technologies.
