The figure 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 work and his dislike for physical activity, her husband gave up early, leaving her and the tall, dark, and smelly trainer to train regularly every day. However, as the days went by, he noticed the strange changes in his wife every time she returned from training, suspecting her of having an affair after seeing her and the trainer looking very intimate. He secretly placed a recording device in his wife's gym bag. The result was a big shock to him when he turned on the recording device, hearing only moans and the sound of skin continuously touching each other...