Ancient goddess Ling Xi awakens after sleeping for three hundred years, needing to find the twelve scattered spiritual power fragments in the mortal world. She attends a high official's birthday banquet, accidentally gets involved in the Xie family's murder case, and makes an agreement with Xie Wei to investigate the case together. Along the way, the two uncover heavy mysteries such as fox demon disguise, identity replacement, and merman sorrowful song. Behind-the-scenes arch-enemy Demon King Xuan Jin secretly manipulates the emperor, stirring up court calamity. Ling Xi enters seclusion to build up her strength, Xie Wei guards her with his body, and the two join forces to fight against the Demon King. Although the great battle severely damages Xuan Jin, he has not perished, and the crisis still lurks.