PE teacher wants to become an English teacher? This is not an impossible thing, but for the protagonist of the movie, Cheon Seung-geun (played by Kim Soo-ro), who works at a famous private school in Seoul's Gangnam district, it is a very difficult task. In the past, he was known as "Iron Rice Bucket" and taught students how to play sports on the field with great vigor, but when it rained and he had to teach indoor classes, all he could do was let the students study on their own - because teaching was not his forte. In the sports world, he was known as someone who wanted to live a perfect life with a healthy body, but when it came to "English," he was undoubtedly a "fool." Recently, the competition between schools to attract students has become increasingly fierce, and from a "strategic" point of view, the school has decided to fire PE teachers and hire more English teachers. Even Teacher Cheon, who has close ties with the chairman, cannot escape this fate. To avoid being laid off, he made a strange suggestion to his superior: the lecture would be given to the parents of the students, and if they approved of his public English class, he would be allowed to successfully "transform" from a PE teacher to an English teacher. From then on, Teacher Cheon began a cruel "Spartan training."