An authentic 18-year-old girl, Riko, is thoroughly teased and exploited. This story exposes the allure of her unbalanced body—no longer a child, yet not quite an adult. Shy and timid, Riko has just celebrated her 18th birthday, and her nervous hesitation reveals her desire to hide her feelings. Deep between her fingers, her wet labia glisten. When suddenly asked, "Have you ever masturbated?" Riko quietly nods. Prompted by the adults, she begins to masturbate, her cheeks turning pink as she's enveloped in ecstasy. Then, a wicked adult fully penetrates Riko's innocent pussy. A thrilling narrative unfolds, intertwining her strangely unbalanced physique with pure, innocent emotions.