Madoka lives with her husband and father-in-law. His father-in-law, whose hobby is shogi, sets a condition that if he loses, he will have to take off Madoka's clothes in order to play against his rival shogi opponent, Isoyama. And Madoka, who was humiliated in front of her stepfather, gradually becomes absorbed in sexual intercourse with her old man, and develops into a physical relationship with her stepfather...
