Mu Chun is the younger brother of "Unrestrained" Mu Hong. The brothers are from a wealthy and influential family in Jieyang Town. Mu Chun excels in martial arts and wields a saber in battle. Mu Chun is one of the leaders of the Liangshan infantry. After the campaign against the rebel leader Fang La, he declines the emperor's offer to make him an official, but returns home where he leads the rest of his life as a commoner.