Within the shadows of the jianghu, Dark River is the most secretive assassin organization of all, made up of three families: Su, Xie and Mu. When the Great Chief who commands them is poisoned and his life hangs in the balance, the three factions seize the moment and rise in rebellion. Su Muyu leads Spider's Shadow, the guard unit sworn to protect the Chief. He brings in Bai Hehuai, a miracle doctor from Medicine King Valley, to treat him, while fighting off killers sent by every family. Yet his best friend, Su Changhe, has joined the plot to assassinate the Great Chief on behalf of the Su family. The result is an action fantasy built on martial arts intrigue and divided loyalties.