Yuji just got himself a new board game and he can't wait to play. What Yuji doesn't know is that the game possesses secret powers - sexual powers, to be precise. He and his stepmother decide to give it a try. The game requires drawing cards from a deck that have sexual instructions on them. Though it starts out innocently enough, Yuji soon experiences sexual feelings for his opponent. As the game progresses and the sexual tension escalates, it culminates in a sexual free-for-all with his stepmother and stepsister.