Rena is a young wife who lives a simple but happy life with her kind husband. One day, a man named Nakata appears in the neighborhood. Claiming to be a jeweler, Nakata recommends a ring to Rena at a low price. However, the proposal is a wicked trap! Nakata makes Rena sign a contract with clever words and demands a large amount of money. He forces the bewildered Rena to open an "illegal sex business using his home as a store" and sell her body to the vulgar men who live in the underground industry...