Ai Taifuuji is a Japanese high school student with black hair, blue eyes, standing 1.56 meters tall, weighing 48 kilograms, and possessing measurements of 80-56-84. She transfers mid-year to a new school where her mother, Haruka Taifuuji, has also started working as the health teacher. Ai exhibits significant naivety and dependence, maintaining an intensely close relationship with her mother. Unaware of the full circumstances behind her mother's job transfer, this naivety renders her vulnerable.

A group of students exploits this vulnerability, blackmailing Ai. They threaten to fabricate information that would get her mother fired unless Ai submits to their sexual demands. The situation intensifies when the school's chemistry teacher, Sakuma Takahiro, targets both Ai and Haruka. Takahiro employs aphrodisiacs and psychological manipulation to coerce female students into his "harem." Ai complies with the exploitation, believing her submission protects her mother. Simultaneously, Haruka capitulates to Takahiro's demands in an effort to shield Ai. This mutual sacrifice, where each endures abuse to spare the other, defines their core dynamic. The narrative consistently portrays Ai as a victim of exploitation.