In the world of demons and spirits during the prosperous Tang Dynasty, Shen Wang, a demon tamer who commands demons through memories, awakens a demon pact on the night his family is massacred. Every demon he commands grants him a portion of power but takes away a fragment of his memories. As he wanders the spirit realm while being hunted by the immortal sects, each demon pact scroll he obtains brings him one step closer to being reborn as the Lord of Ten Thousand Demons. To seal away the Lord of Ten Thousand Demons, he sacrifices all his memories and becomes a blank slate, remembering only that his younger sister, Shen Nian, is imprisoned in the Heavenly Prison of the Immortal Realm. The demons repay him with fragments of their own memories, bringing him back to life. He commands six demons once more, storms the Heavenly Prison, and rescues his sister. He then obtains the remaining fragments of the Name to complete and fully seal all seven demon pact scrolls. Above the River of Forgotten Memories, his lost memories rise to the surface. He has forgotten who he is, yet still remembers that he must save her.