Saka and Ikio are a married couple in their second year. Saka recently confided to her friend over the phone that her husband no longer invites her out at night, and this conversation was overheard by her brother-in-law Seishi, who had just moved into the same apartment building. She is then pressured into a physical relationship. Although she knows it's wrong, curiosity and Seishi's insistence lead Saka to fall into the abyss of pleasure...
