Jay, an international student from Thailand, comes to Korea to see his friend Seong Hun. The two enrolled in the same college class called "Health and Happiness" and need to submit a physical body assessment for their final project. While Seong Hun already works out regularly, Jay isn't in the greatest shape and struggles in the gym. Enter Jin Uk, a personal trainer who takes a special interest in Jay, much to Seong Hun’s displeasure. However, there's something strange about Jin Uk. Despite his ...