When my husband is away from home on a business trip, my favorite brother who lives at my parents' house suddenly comes to Tokyo. - Natsuki, her brother and child, propose to use an empty room, and she decides to indulge in favor. When I asked such a brother why he moved to Tokyo, he said that he broke up with her because of sex, so he wanted to hone his sex technique in customs. However, because the prostitute he was looking for had quit, his brother, who was at a loss, proposed a practice table against his sister's personality, and he could not refuse the request of his favorite brother and accepted it slurred.