STARS-081 Mahiro Yui was gangbanged after her boy's outfit was discovered...

In order to save her younger brother, who attends an all-boys school, from being bullied, her older sister Mahiro disguises herself as a man and sneaks into the school, and is able to grasp the bullies' weaknesses and make them stop the bullying. - However, when the bullies find out that Mahiro is a woman, Mahiro is attacked in a counterattack. - At first, Mahiro was strong-willed, but he gradually fell into the pleasure of masochism, became addicted to lust, and became wild.