One day, humanity was wiped out by an alien attack. We happened to be out in space on a school trip but the aliens, realizing their mistake, captured us. They began creating a human ranch to breed humans and restore their numbers. Forced sex like livestock, semen injected directly into uteruses by machines and automated birthing systems— all to save humanity from extinction. While everyone gradually went crazy, one girl desperately tried to hold on to her sense of self...