A college student who recently started living alone due to his academic pursuits. His younger sister, envious of his newfound independence, frequently visits his room. When she asks if she can use his room for intimate encounters with her boyfriend, he declines because friends might drop by. Feeling rejected, she comes up with a devious plan... As she pushes him further and further mentally, he discovers a sadistic side to himself. He revels in destroying their friendship and turning his brother into a masochistic slave, all while mocking his helpless state. Note that the recorded content may vary depending on the distribution method.

進学を機に一人暮らしを始めた大学生のオタク男子。そんな男を羨ましく思った妹は頻繁に兄の部屋を出入りするようになった。彼氏とセックスする場所として部屋を貸してと交渉するが友達が来るからと断られた妹。困った妹はふと思いついた極悪非道なアイデアを実行することに…。自分の兄を精神的に追い込んでいくうちに目覚めたサドという性癖。友情を破壊されマゾ化させられた兄の姿を嘲笑う。※ 配信方法によって収録内容が異なる場合があります。