Mirei ends up repeatedly engaging in adultery with Taichi, her son's friend. It began when she caught Taichi secretly taking her underwear from the drawer, visibly aroused. Rather than scolding him, Mirei feels unexpectedly pleased, thinking, "Even an older woman like me..." Neglected by her husband and driven by loneliness and a mischievous impulse, she starts provoking Taichi, giving in to rising desire and indulging in pleasure she hasn't felt in a long time. This encounter becomes a thrilling new stimulus for her, marking the beginning of a new relationship.