Umi is on good terms with her husband, but she is not blessed with a child and spends her days feeling depressed. - One day, her brother-in-law, Kyoichi, came to her house for a memorial service... - Kyoichi, who has a strong sexual desire and loves women, relentlessly taps into her deepest desires. - ``I was just swept away...'' Umi tells herself, and they have a one-time relationship. - However, the pleasure is quickly overwritten by the relentless caress and stimulation of his cock that penetrates to the top of her brain. - And before she knows it, Umi falls for Nagasare's secret affair with her brother-in-law...