To save her brother from bullying at an all-boys school, Mahiro, his sister, disguised herself as a boy and infiltrated the school. She exposed the bullies' weaknesses and managed to stop the bullying. However, once the bullies found out that Mahiro was a girl, they retaliated by raping her. Initially defiant, Mahiro gradually fell into the pleasure of masochism, drowning in lust and writhing in ecstasy…
