Original doujin manga, 2nd of the series. It all started with a kiss, and a brother and sister both became hooked on an incestuous relationship. During summer vacation the brother, who now lives by himself...

When Kaoru was summoned by his Mom and went back home after several years, he was asked to take care of his uncle because she was going abroad. His uncle Kei is much younger than his Mom, and Kaoru really...