At a hot spring resort where no one knows the siblings' blood relation, a brother heads to an inn alone with his secretly kept "little sister." The moment they arrive, he latches onto her still youthful breasts and thrusts his cock into her virgin-like pussy. As she moans softly, "Onii-chan..." with a pained yet longing breath, their forbidden bond grows ever deeper. This trip becomes a private haven where only their hidden desires are fulfilled. *No one appearing in this work is under 18 years of age.