Sage, as a chambermaid of an extinguishing hotel, somehow rescued someone's son that she later knew as a vampire. In exchange for her generosity and kindness, she received an offer to work in a different place with different people to serve. Less she knows, she agreed without a doubt and thought of having a better future. The vampire warned her to wear a suitable costume as a disguise and never get it off no matter what happens. At first, she thought they might have a costume party. And she was given a task to become one of the delivery girls who deliver food and other goods to everyone's whim and later to the demon prince.

Five Friends decided to go for a trip in such a place when they didn't notice where they are heading to and leads to a place named Sheol's Pit. They didn't know what's the meaning of the name until they started to play the game.