BAGR-066 A slutty little sister who distorts the friendship and sexuality of her otaku brother, Seira Kuwahara

A geeky college student starts living alone after moving on to college. His younger sister, envious of her brother, begins frequenting his room. One day, she tries to get him to lend her her room so she can have sex with her sex friend, but he refuses, saying that his friends will be coming over. Troubled, the younger sister suddenly comes up with a diabolical idea and puts it into action... As she pushes her brother to the brink of mental breakdown, her sadistic tendencies are awakened. She laughs at her brother, who has had his friendship destroyed and been turned into a masochist.