umi has a happy marriage but struggles with infertility, leading to gloomy days. one day, her brother-in-law, kyuuichi, visits for a funeral. with his strong sex drive and love for women, he relentlessly awakens her hidden desires. "i was just carried away," umi tells herself, giving in to a one-time affair. but his intense caresses and thrusts overwhelm her, replacing her feelings with pleasure. before she knows it, umi finds herself drawn into secret trysts with her brother-in-law.