The son went on a hot spring vacation with his father and stepmother Hijiri Maihara, the new wife he just married recently. He feels a lot of pressure from his father during this 2-day, 1-night trip, as his father insists that he has sex with his wife and gives him a grandchild. However, whenever he approaches his wife, she always refuses, stating that she is not ready for children yet. Feeling bored, he went out of the room intending to soak in the hot spring to relieve his stress, only to find his stepmother naked soaking there, which was quite an intense situation...