In an imaginary world where Korea is one of the world's leading nations in martial arts, its government encourages high schools to set up martial art classes to develop talented martial artists. As the government provides numerous benefits to the students of these classes, almost all teenagers dream of being selected for the special classes. Among the martial arts classes all over the country, Namil High School's Martial Arts Class 3 is the most famous.

A short, weak freshman named Jitae, whose physical appearance is the very opposite of a typical athlete, looks to join Namil's Martial Arts Class 3. Maria, a genius martial artist and international student of Class 3 from Brazil, happens to notice the unique talents that Jitae possesses-a double jointed body and the ability to read the movement patterns of his counterpart while fighting-that are ideal for Brazilian Jiu-Jitsu. Julia also knows about Ji-tae's missing father, who used to be a famous martial artist. Through numerous fights with Maria and his other classmates, all who have mastered different martial arts themselves, Jitae gradually becomes a martial artist specializing in Brazilian Jiu-Jitsu. All the while, he continues searching for his missing father with Maria...