Meeting his cousin Shion Yumi, who often doesn't wear a bra. A guy went back to his hometown to visit and conveniently visited his cousin, who they used to play with. But now they're both grown up, and the younger sister Shion Yumi, has become more attractive than ever, often wearing a shirt at home that shows her nipples, extremely stimulating. After that, the two had incestuous sex with each other right at home, extremely attractive.