Synopsis：17 year-olds Sung-eun, and Mi-sook are always curious about sexual matters that nobody teaches them about. One day, new teacher Bong-gu, a handsome and well bred stud,arrives at school and begins to teach their class. He becomes an object to watch and study. Bong-gu, although he seems fine on the outside, suffers from an unknown illness that makes him fart whenever he feels aroused. Three girls learn about this and they go on a mission to make him fart.