After reaching adulthood, Shion, a boy who was unable to manifest his magical abilities, was left under the care of a family specializing in magical research. One day, during a horrible incident, he finally unveils his talent, and is taken under the wing of an experienced healer named Rui, who promises to teach him how to control his powers. However, in order to properly handle magic, the boy needs to possess deep knowledge of sex.
Thus, Rui decides to go against her marriage vows and take Shion’s virginity, while simultaneously teaching him how to properly satisfy a woman. This arrangement continues until he can master his magical abilities.