Riona moved to the city after graduating from the countryside, got married to Kazuo whom she met there. While struggling to pay off their mortgage, they lived a hectic but happy life. Even after moving to the city and getting married, Riona, who was originally not fashionable, still wore her signature black-rimmed glasses. Of course, Riona had nothing to do with romance, but she was persuaded by Kawakami, an insurance salesman who visited her, and gradually fell into the depths. Her husband, oblivious to the fact that his wife was becoming more beautiful with each experience of feminine pleasure, continued to be unaware. And Riona became increasingly addicted to the depths.