Ryu's husband is a successful businessman, she lives a happy life with him and his family. Her brother-in-law, Toshio, lost his job due to the company's restructuring. Even though I've been looking for a job everywhere, I haven't been accepted to any company yet. Pressure from his father and even being despised by his younger brother made Toshio stressed. The only thing that could help comfort Toshio was looking at his sister-in-law's beautiful body. Toshio often peeps at the lovemaking scene between his younger brother and his wife. When his younger brother went away on a business trip, pressure from his father as well as being taught by his younger brother made Toshio unable to control. At night when Ryu was sleeping alone, Toshio forcefully invaded her body. The next morning, when he calmed down, Toshio realized his mistake, he immediately went to apologize and ask Ryu for forgiveness. Thinking she would never forgive him, he was about to leave when suddenly Ryu grabbed his hand and looked at him with deep eyes. And the two gradually understood each other, they voluntarily came together, and started this wrong relationship… Fucking sister-in-law when brother is not home