Due to her husband's absence, Yumi has to live with her son-in-law, Kiyoshi. However, there was no way Yumi's body could withstand a life without a man, and she started having an affair. One day, Yumi receives a package. Yumi feels aroused when she sees the vibrator inside, and begins to masturbate even though she feels suspicious. A few minutes later, Yumi Hatsuta's phone rang. The phone call from the man who said, ``I know everything about you,'' was the beginning of a hell that even Yumi could not have imagined...