Ayaka is an older sister who is kind and reliable. She has been your childhood friend since you were young and is now your girlfriend. Although you are happy with her company, you feel unsatisfied because of a hobby that you keep hidden from her. This hobby involves S&M, which includes buying tools for personal use, such as staring at them and touching them. One day, while expelling yourself of these urges, someone entered your room and saw the secret. You tried to set a trap by turning around to see who discovered it, marking the beginning of an abnormal relationship between you two.