This work tells the story of an abnormal system called "Semen-Drinking" introduced at a certain school. Under this system, all female teachers are forced to drink the sperm of their male students—a cruel and inhumane rule. Rui Saotome, a newly appointed teacher, carries out this duty every day while questioning the true nature of the system. Set in a disturbing yet realistic environment, the story explores her inner turmoil and her quest to uncover the dark truth behind the institution.