A brother-in-law who decided to live with his younger brother and his wife for a while due to work reasons. - In fact, the younger brother and his wife, who live in peace, also raise dissatisfaction and loneliness to their husbands who do not work hard to make children. - The brother-in-law who sensed such a heart approaches Yukino in place of his unlucky younger brother. - Yuki refuses to be unfaithful, but her pleasure cannot be suppressed by her repeated blame of her brother-in-law, and she has a relationship. - Yukino, who was fascinated by the gentle and rich caress, seduces her brother-in-law and drowns in an unfaithful relationship.