Aika grew up with wealthy parents without encountering any inconveniences. At her parents' suggestion, she married a man who lived far away and led a mundane life. One day, she was taught how to make papa katsu by her classmates at school and met a man who showed some interest in her. While she felt guilty, she was also uplifted by her own discomfort. When she met that man again, the kind man tied Aika with a rope. At first, she found it enjoyable and wanted to feel a little stimulated, but over time, it became an addiction.