Silently watching his sister being raped by her friends

Silently watching his sister being raped by her friends. Falling in love with his older sister and repeatedly filming scenes of her changing clothes and leaving them on his phone, the young man was discovered by his friends and threatened to spread the clip if he did not let them come to his house to meet his sister Hikari Ninomiya. He didn't expect that his friends would use that video to force her to have sex. That weak girl was easily intimidated and had to do what the uneducated students forced her to do. He was helpless and could only watch his love being raped, it was so miserable!