Kazuya made his wife angry during a marital dispute. While he was at his wit's end, his wife returned to her parents' house in a rage, and he was left worrying...his wife's sister, Naoko, offered to give him advice. Kazuya was completely at his wit's end, unable to find a solution, and he let his guard down in the beautiful and caring Naoko. However, Naoko's real purpose was not to settle the marital dispute, but to relieve her sexual frustration with Kazuya...