Lu Qingyuan, a chivalrous swordsman from Jiangnan, travels north with a keepsake left by an old friend to visit the hermit Lin Mochen. He hopes to uncover the truth behind the “Green Robe Case” from twenty years ago, which led to the destruction of dozens of martial arts sects and concealed the ambitions of a mysterious force known as the Cold River Pavilion. Along the way, he meets Lin Wanjing, Lin Mochen's daughter. From mutual suspicion to joining forces, the two must face the Cold River Pavilion's assassins and the schemes of martial arts sects, while also unraveling the secrets hidden by the Lin family. As the investigation deepens, Lu Qingyuan discovers that his own origins are closely tied to the Green Robe Case, and that Lin Mochen was a key figure in the events of that year. In the end, the three join forces with the righteous to foil the Cold River Pavilion's plot to control the martial world and restore peace to the realm.
