After being beaten by local thugs over a steamed bun, a quiet young man known only as “the boy in the grey shirt” is rescued by a mysterious elder who takes him to a hidden martial arts sanctuary. Under the guidance of four eccentric masters, he trains relentlessly and discovers his own strength and purpose. But when the elder who saved him is killed while protecting others, the boy breaks his promise to never use his skills for violence. He returns to confront the gang leader Wen—once a fellow student of the same master—unleashing the techniques of all his teachers in a final showdown to reclaim his dignity and honor.