Prestige's exclusive actress Maria Aine is my beloved big sister! Just as I started living on my own, my drunk sister suddenly barged into my home. Seeing her lying there in such a revealing outfit, I accidentally got an erection, and to make matters worse, she caught me and started teasing me... Threatening me with words like "What big sister says is absolute," she suddenly declared she would move in with me, constantly tempting me with her erotic body! To fight back against my sister, who has been escalating things since we crossed the sibling boundary, I ordered a certain cosplay outfit and some toys. While carefully observing her expression, which didn't seem to mind at all, I began to aggressively push her further...