Taibai Jinxing discovers that a force has suddenly appeared in the human realm, beyond the control of the Three Realms. Its members cannot die, are immune to fire and water, and their names aren't in the Book of Life and Death. The Jade Emperor suspects there's a traitor in the Underworld, so he establishes the Yin-Yang Inspectorate and appoints Qiao Gaoxing, a mortal who was once a boy attendant in Taibai Jinxing's service, to investigate in secret and root out the traitor. But after taking office, the nobody Qiao Gaoxing's first move is to use his position to start a business. As a series of coincidences unfold, he realizes that things may not be so simple.
