Her older sister is physically weak and cannot have children. Her younger sister, Hina, asks her to have sex with her husband to make a baby. Hina agrees for the sake of her beloved sister, but contrary to Hina pure and innocent feelings, her brother-in-law becomes obsessed with Hina young body and loses himself in it. As her brother-in-law's demands gradually escalate, changes begin to occur in Hina Kokoro and body...