Chigusa has been married to her husband Kenji for a year and has been living happily ever after. One day, just before their wedding anniversary, her husband asks her if he can let her stay with him while he looks for a new job. Furthermore, her husband is scheduled to go on a business trip, so she ends up spending her anniversary with her brother-in-law. After seeing her husband off, she thought she had gotten along with her friendly brother-in-law, but Kazuhiko, who was aroused by Chigusa's defenseless appearance, pushes her down. Since that day, the pleasure that was engraved into her body keeps coming back to her mind...