When the beautiful older sister Sakurako gets engaged, the relationship between the brother and sister, which has been supporting each other until now, is shaken. For the first time, he realizes his love for his sister Sakurako and Kokoro jealousy towards her fiancé, and his blood-related brother also desires Sakurako's fine and voluptuous body. From the day that he first had sex with his brother, who he had never paid any attention to before, Sakurako's confidence turns to doubt, and he falls into a muddy human relationship, loving both of them in a lewd manner. In front of his sleeping fiancé, the brother and sister deeply bond and Sakurako climaxes in a lascivious incestuous creampie sex.