Michiru, the stepmother, lives alone with her stepson Yoshio while her husband is away on a work assignment. Recently, Michiru has become increasingly aware of Yoshio's gaze, causing her to feel confused as she starts seeing him as a man. Meanwhile, Yoshio secretly pleasures himself while fantasizing about Michiru being seduced by her classmates, moaning in ecstasy. As their hidden desires grow stronger, their feelings deepen and gradually evolve into a real romantic relationship.