Biology teacher Yumi Shimaoka is gentle by nature but has a strong sense of justice, often scolding students in a way rarely seen these days. As the student council advisor, she is highly popular among top students. Among them is a boy named Kohei Tsujita, who repeatedly provokes her on purpose. His twisted affection sets off a chain of events that drastically changes Yumi's life. One day, she faces the worst nightmare of her existence. Through Tsujita's actions, the dormant sensuality within her gradually awakens, leading her into uncharted territory. This intense story draws readers in, stirring their emotions as they follow her transformation.