In this world, the number of boys is so low that sexual crimes committed by girls have become a social problem. The nature of these crimes involves girls exposing their vaginas and breasts to boys in rarely-used back alleys, causing the boys' penises to become erect, having sex with them, and forcibly ejaculating inside their vaginas. I am Tomo, a 13-year-old boy. Fortunately, I haven't been targeted by these crimes yet, but I've reached the age where girls start targeting me, so I'm constantly anxious.