A guy, a high school student, fell in love with his older sister. Knowing that this is incest, his emotions are always dominated by her beauty. He secretly filmed her changing clothes and had many clips on his phone. One day his friends discovered those clips on his phone, they took it and were going to use it to threaten his sister Hikari Ninomiya and force her to have sex. Indeed, the next day they went to Hikari's house and raped her. The younger brother could only watch helplessly as she was fucked.