Ai Sayama, exclusive to Goro Tameike, makes a limited one-time appearance in this live-action adaptation of the original work by Torotoro Mel! Junpei shares a room with his college-student sister, who enjoys cosplaying night after night. One day, during a cosplay photo shoot, things escalate and his sister begins to strip off her costume. Usually, Junpei just suffers in silence, but he finally reaches his limit and secretly masturbates to photos of his sister. However, just before cumming, he is caught by her. Instead of being furious, she surprises him with a special costume for their first time fucking. From then on, her daily cosplay servicing begins.
