Chigusa has been happily married to Kenji for a year. Shortly before their anniversary, Kenji asks if his older brother, Kazuhiko, can stay with them while looking for a new job. Then Kenji is sent away on business, leaving Chigusa alone with her brother-in-law on their anniversary. After seeing her husband off, she begins to relax around the friendly Kazuhiko—until her unguarded appearance arouses him and he forces her down. From that day on, the pleasure etched into her body keeps returning to her mind...