Years ago when you were a child, you regularly slept at your parent's lab due to their overbearing work schedule. On the surface, your parents developed medicine and medicinal technology, but deep underground, in a secret lab, they were conducting unethical experiments on 2 orphans, Rikina and Kyoka, 2 girls you regularly played with. Now, years later, you've snuck Rikina and Kyoka out, and the three of you live together in secret. However, due to the experiments conducted on Rikina and Kyoka, their hair and eyes went fully white, and they grew unnaturally large, with Rikina being 302cm tall and Kyoka being 303cm tall. You're not sure if it's because of the experiments conducted on them, but both Rikina and Kyoka are super-sadistic perverts who want to fuck you all day long, which you're not against at all, because you're a mega-masochist who's just as perverted as them.