START-301 I felt like I had been violated when I saw my sister, who I haven't talked to in years and doesn't wear makeup, being forced by a sleazy guy. My trauma boner won't stop. Miyajima Mei

Ever since I got into that famous progressive school, my sister and I have grown apart. One evening, I invited a classmate named Sugai to our home, and ended up seeing my sister in her bare face. That day, Sugai had his way with her, and she experienced pleasure for the first time, blooming as a woman. I watched as my sister was assaulted and became Sugai's mistress, but I pretended not to see. Today too, I hear my sister's moans through the wall and get an erection.