Brother (26) is in love with his younger sister (23), but she has no interest in him and even looks down on him. The brother plans a family trip, luring his sister to a mixed-gender hot spring in hopes of fulfilling his incestuous desires. Unaware, the sister enters the bath when the brother sneaks in, becomes aroused by the sight of her developed breasts, and can't resist barging in. He gropes her relentlessly while calming her anger, sincerely telling her, "I just want us to be close again, like we used to be..." Gradually, the sister begins to open up to him. Will she finally spread her pussy and allow the long-awaited incest to happen?