Satomi Suzuki's husband on a business trip away from home left her at home to live with her husband's previous son. The boy was a university student, named Yuichi. The absence of her husband for too long made a woman in her youth feel more and more deprived, frustrated, and uncomfortable, adding to the scene every day of witnessing her husband's stepson with a big erect penis every day while sleeping. Every day she refrains from masturbating, but having exceeded her limits, Satomi has secretly sucked her son's penis...