In the future, sexual reproduction is prohibited. A girl who doesn't know about sex starts to find out about forbidden pleasure after meeting a man from an underground group... ! In the year 2XXX, all information about sex has been blocked, and people had forgotten about it. However, a rebel group has been allowing and promoting the act of sex in an underground building! A college girl named Shino sees the "scene" and gradually finds out about the forbidden pleasure with a man called Yamato.