相姦遊戯

A board game sample gotten from a toy company's salesman who said will help "get along with the people you play with".
However, this game is no ordinary game.
The protagonist decides to play it with his mother and little sister, but without noticing, the moment you start playing the game, you became unable to leave the room or ask for help. They will have to keep rolling the dice to reach the end in what became a closed room. Then, depending on the square they land on, they will be forced to take erotic actions...