To save her younger brother from bullying, Mahiro, his sister, disguises herself as a boy and infiltrates the all-boys school. She manages to stop the bullies by exploiting their weaknesses. However, once the bullies find out that Mahiro is a girl, they retaliate and assault her. Initially defiant, Mahiro gradually succumbs to the pleasure of masochism, drowning in lust and writhing in ecstasy･･･
