Uta and her stepbrother began living together after their parents remarried. In the midst of her rebellious phase, she physically couldn't stand his presence and felt irritated every time they met, but being in puberty, she masturbated in her room every day. Little did she know, this self-pleasure would be the cause... One day, their parents were away for three days, leaving the two siblings alone. The stepbrother had actually secretly filmed his cheeky little sister's solo sex, and used it as leverage to demand sex. Although it was humiliating to have his cock shoved inside her, their sexual chemistry was too good, leading to 72 hours of constant climaxes.