The Hirose couple met as co-workers and have been married for three years. With her husband Yugo making a decent income, they are living a smooth life. However, recently, Riona has been refusing whenever Yugo invites her to have sex, making up excuses. Yugo begins to sense a discord and, although he feels bad for her, he hires a private detective to investigate Riona's daily life. A few days later, he receives a memory card from the detective, which shows Riona in an indecent pose being trained by her lover...