The infamous martial arts master, Mu Tianhou, is suddenly ambushed, causing a stir in the martial arts world. His two upright disciples, Zheng Dongting and Zu Beiqiu (the two seemingly useless brothers), meet as a result. To help their junior brother Zu Beiqiu find his wife, whom he hasn't seen for ten years, and to find the true culprit who murdered their master, a renowned constable and a wealthy young man unexpectedly embark on an adventure to deliver a letter of divorce. Arriving at the Luo family estate in Yangzhou, they witness the massacre of the entire family and are wrongly accused of the murders, earning them the nickname "The Twin Fiends of the Central Plains." One possesses martial arts skills he cannot use (Zheng Dongting), while the other has skills he cannot use (Zu Beiqiu). Although the brothers intend to clear their names, the misunderstandings between them deepen, and the righteous factions of the martial arts world rise up against them. Having survived perilous battles such as the Battle of Shuyu Tower, the Night Battle of Shezhou, and the Debate at the Hall of Righteousness, the two discover that it's all part of a grand conspiracy against them...　　To uphold the code of the martial world, Zheng Dongting uses the divine sword "Full Sky of Stars" to defeat the villain Gong Tianying at the Luoyang Sword Tournament, a gathering of martial arts elites. Although Zheng Dongting breaks his promise not to use martial arts, he gains the forgiveness of various sects in the martial world. After the Sword Tournament, the two brothers embark on a westward expedition to Tianshan, defeating the Kunlun Demon Sect's overlord, Honghua, to avenge their master...