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.