Body shape is always a concern for women, no one wants to have a bad appearance, that's why Ai invited her husband to the personal gym to exercise under the guidance of a male trainer. However, due to the nature of his job and his dislike for exercise, her husband quickly gave up, leaving her and the tall, dark, and handsome trainer to train regularly every day. However, the more days passed, the more he noticed the strange changes in his wife every time she returned from the gym, suspecting her of having an affair after seeing her and the trainer looking very close. He secretly placed a recording device in his wife's gym bag. The result came to him as a big shock when he played the recording, only to hear moans and the sound of skin continuously touching each other...