A young wife, Eri, who is not satisfied with her husband's life, harbors no hatred for her brother-in-law who lives with her. One day, she happened to have a physical relationship with her brother-in-law. Her joy of releasing her body, which was depressed by unsatisfied days with her husband, gradually escalates. Her younger brother's friends are involved, and the curtain rises on her lustful days that she can't tell her husband.
