After 25 years of marriage and with a daughter now grown, Natsuko lives an ordinary yet happy life. She shares a comfortable, distant relationship with her husband, lacking any real complaints—until she meets Kaneko, her daughter's senior. At first just an acquaintance, Kaneko instantly falls head over heels for Natsuko. His pure, shy demeanor awakens memories of her youth, stirring emotions long buried. "I'm seriously in love with you, Natsuko-san..." "Oh... what are you saying?" "I know it's inappropriate. You have your husband and Kona-chan... I know this love can never be fulfilled." "...Kaneko-kun..." "Just one last thing... can I hold your hand?" "Huh?... I don't know..." "After this... I'll let go." Unable to resist, Natsuko takes his hand. In that moment, her dormant heart begins to race. The long-forgotten thrill of romance shatters her reason, pulling her into a forbidden affair.