Nao Hayashi, 46 years old. Her husband is away for work. Her son Toshio tries to kiss her but gets rejected, leaving him heartbroken. One day, Toshio starts reading a porn magazine right in front of her. Surprised, Nao confronts him, asking why he's doing such a thing. He pleads with her to teach him how to kiss. At first, she agrees half-jokingly, but as Toshio remains unsatisfied, their relationship gradually escalates into something far more intimate. Family bonds and the parent-child relationship take a dramatic, irreversible turn.