At the start of his son’s new school term, Yoshino joins the PTA and meets Ayano, Mari’s mother. The two are unexpectedly appointed as officers, and he is immediately drawn to her friendly, refined manner. But beneath that elegant exterior, Ayano is a shameless married woman who loves stealing other women’s husbands. While working in the gym storage room, their conversation turns to romance and she suggests, “Why don’t we kiss right here?” Yoshino tries to brush it off, but she grabs him and forces a kiss. From that day until his son graduates a year later, the pair lose themselves in secret, passionate PTA encounters through every season.