Momoka Ogawa and her husband move into their new home. The husband has always been fond of his wife Momoka's sporty ass, but recently notices her figure gradually becoming softer and plumper. Meanwhile, their neighbor, a man who claims to be an esthetician, becomes increasingly interested in the changes to Momoka's body, indulging daily in fantasies about her. One day, he comes home to find Momoka performing mysterious exercises. Captivated by the sight, he finally approaches her. When Momoka opens up about her insecurities, the man suggests she try some professional tightening treatments at his place. Tempted by his offer, Momoka immediately agrees. Overjoyed at the chance to finally touch the ass he's long desired, the man eagerly invites her into his home.