Eri, a young wife who is not satisfied with her life with her husband, has a fond feeling for her brother-in-law who lives with her. One day, by chance, she ends up having a physical relationship with her brother-in-law. The joy of releasing her body, which had been pent up from the unfulfilled days with her husband, gradually escalates. She even gets her brother's friends involved, and so begins a life of lust that she can never tell her husband about...