An ordinary middle-class family somewhere in Japan. But the parents are not there. The older brother has feelings for his younger sister that go beyond those of a simple relative. The older brother shows a strange interest in one part of his sister's body: her buttocks. He has an extraordinary obsession with touching his sister's buttocks, smelling them, tasting them, and feeling their texture. He takes pictures of her buttocks bulging out of her uniform, and slides his raging cock into her crack while she sits on his face. The younger sister even accepts the play of cutting her clothes, offering her oiled, peachy buttocks to her friend... This controversial work depicts the abnormal love between brother and sister in four parts.