After failing college entrance exams twice, Wataru has become what society calls a hikikomori. Noticing his son's situation, his father asks Yuu, the wife of a friend who once worked as a private tutor, to help him study. Yuu gladly accepts and begins tutoring him, but struggles with Wataru's complete lack of motivation. Desperate to help him focus, she decides to use her stunning figure to try increasingly erotic approaches. As their sessions progress, the story unfolds with Wataru's changing emotions and Yuu's true feelings coming to light.