My sister was taken advantage of by an ugly man who ejaculated inside her from behind, and I was powerless to stop it. (Himekawa Yuna, MIGD-771)

My sister loves me the most, but she was forcibly taken by those perverted, ugly men and forced into a doggy-style position where they raped her and ejaculated inside her. When I got home and saw the terrible state of my sister, she begged me for help, but I was powerless to do anything and could only watch helplessly as she was taken away...