The husband often criticizes the body and recently has shown many strange behaviors, afraid of infidelity, so Ichiki decided to get breast augmentation to hold onto this husband who is about to change his mind. However, just after the successful breast augmentation, the husband had not even had a chance to admire it when the lucky brother-in-law enjoyed it first. Due to being away on a business trip, only the wife and the older brother could visit for a few days. That's why on the day she got her breasts done, the brother-in-law was attentive in picking her up, and that evening they both started drinking to celebrate. With alcohol in their system, seeing the alluring round breasts of his sister-in-law, the brother-in-law couldn't control himself, continuously fondling her large breasts and then indulging in her wet vagina because of her arousal. That night, they crossed the line in the relationship between brother-in-law and sister-in-law, engaging in a secret affair behind the unfortunate husband's back.