Yuichi was Kokoro to Nao, who was always dressed provocatively and had a sexiness that made it hard to believe she was his mother's best friend. Nao, who has a terrible relationship with her husband, would occasionally come over to his house to complain, but on this day his mother was out and Yuichi had to listen to her complaints... Nao's complaints gradually escalated in an unexpected direction, creating a mysterious atmosphere... Nao then smiled seductively and whispered to Yuichi, "Don't tell your mother about this."