Summer vacation-- After returning to his parents' house, "I" resumed with his brother and sister in the countryside. A brother and sister who have grown more feminine than before, even though they still have ○. While talking to her innocently playing in the river with her old smile, Lustful for her healthy burnt skin and her sheer breasts Involuntarily reach for her hand on her chest. "... Huh! Yeah, hmm ... oh, that's no good ... no, oh my god, hmm ..." My brother and sister who are confused but gradually accept him, "I" has committed many times.