Under her brother's control, younger sister Eru has endured sexual abuse since childhood. Forced to obey her brother's aggressive demands, she had no choice but to offer her body. Still physically developing, her body continues to withstand his harsh treatment. When his desire rises, he forcefully thrusts his penis into her mouth and manipulates her body. These acts are always painful—though she resists, she eventually succumbs to her brother's domination, compelled to orgasm. Each time, Eru's heart grows more deeply wounded, entangled in conflicting feelings of dependence and fear toward her brother.