Tsubasa lives with her husband's father, her father-in-law. They are considerate of each other and live in harmony. One night, Tsubasa and her husband are engaged in sexual intercourse. However, her husband is originally weak in that area, and this time too, he came by himself before Tsubasa was satisfied and fell asleep. Tsubasa had no choice but to quietly comfort herself. Tsubasa was sleeping in the middle of the night, and when she threw off the futon because of the strange feeling in her lower body, her father-in-law was playing with Tsubasa lower body. She was surprised and tried to make a sound, but her mouth was covered, and he made her cum with his fingers, saying that she couldn't be satisfied with her son. Then, Tsubasa was made to cum again by the intense thrusts that were incomparable to her husband's. From then on, her father-in-law took advantage of the opportunity to caress Tsubasa and bring her to climax. Tsubasa, who had never experienced anything before with her father-in-law, became a slave to sex, and finally headed to her father-in-law's bedroom of her own volition...