While her husband is away on a work assignment, stepmother Ryouko lives with her stepson Yoshiro. Recently, she begins noticing his lingering gaze and realizes he sees her as a woman. Meanwhile, Yoshiro is tormented by jealousy and anxiety, haunted by fantasies of his stepmother being exposed to his friends' pranks. As their emotions collide, forbidden desires awaken, driving them into an impulsive, passionate affair. Between them swirls an intense connection that transcends family bonds.