Under the guise of personal training, a fitness instructor takes advantage of his client, Chikusa, who's desperate to lose weight. He starts with squats, then moves on to intense core exercises, getting her to open her legs wide for stretching and internal massage. He then forces her to perform oral sex and intense back-door sex, culminating in a raw, deep thrust into her pussy, making her cum uncontrollably. As a reward for her hard work, he injects her with homemade protein shake, promising to continue their "training" next time. Chikusa, overwhelmed by the intense workout and his relentless advances, becomes his loyal client.