Natsuko, a social studies teacher who has been assigned to a boys' school for five years, is witnessed by her homeroom class student, Igarashi, who commits infidelity with a colleague for temporary pleasure. Natsuko is forced to become Igarashi's pet as a condition of her silence. During her class, she constantly resists Igarashi's shameful orders with her mouth, but she begins to feel pleasure in her body.
