From the introduction:
Rapture Academy is an ancient institution of education. Situated in the remote countryside, far from civilization besides a small town controlled by the academy, Rapture is a coed boarding school that serves the wealthy and talented.
The school has a dark secret. Several, in fact. All of the girls are beautiful not through luck, but because they are sent here to be broken into sex addled whores. Some families send disobedient daughters here intentionally. Others are poor and think the scholarship the school offered their beautiful daughter was legitimate.
Once girls arrive, they are sorted into a system of houses designed to divide them and keep them at each others’ throats while the conspiracies, mad scientists, cults, and demons lurking in the school and woods around it all prey on them. It may seem like a normal school at first, but most girls who survive with their sanity intact for any length of time learn to play the game, keeping themselves relatively safe while betraying other girls and throwing them to the monster of the week when necessary to save their own skins.