In the seventh year of Yongjinghe's reign, cases of lost souls frequently occurred in Chang'an. Shen Jingque, the commander of the town night department, was ordered to investigate and met Xiao Jin, the soul attractor. The two discover that the case is related to the blood bat, the witchcraft sect and the yin and yang jade, and involves a thirty-year-old case and a palace conspiracy. They work together to break into the imperial mausoleum, explore the Yin City, break the Gu formation, expose the traitor, and fight against the evil spirits. In the process of guarding Chang'an, they gradually fall in love, and finally explore the truth and defend peace amidst the dangers.
