Delivery boy Sun Zhicheng was saving money to buy a house, and accidentally connected to the "underworld navigation" system that delivers items at the intersection of yin and yang. From then on, he ran around in urban weird stories intertwined with micro-terrors and sand sculptures. Relying on the ancestral copper bell and his greedy and kind-hearted character, he dealt with strange rules such as the girl in red and the shadowless recipient, and delivered the ingredients of Mengpo soup and overtime coffee to Naihe Bridge and the underworld. As his delivery points increased, he unlocked the more dangerous "Reincarnation Line" orders, and gradually got involved in the conspiracy of Zhao Wuyan, the supervisor of the Yin and Yang Order Department, the secret past of Lao Zhou, the owner of the incense shop, and the scientific observations of Shangguan Yu'er, a graduate student in folklore. Sun Zhicheng discovered that the copper bell left by his grandfather was related to the ancient legend of the 'Yin Yang Messenger', and Zhao Wuyan was taking advantage of loopholes in the rules to gain profits and try to turn him into a victim. In one dangerous delivery after another, Sun Zhicheng grew from a rider who only cared about making money to a "crosser" who protected the weak and challenged injustice in the rift between Yin and Yang. In the end, he must face the power behind Zhao Wuyan and the truth of the lost "Yin-Yang Great Contract", and choose his own path of balance at the cost of the wear and tear of humanity and the dilution of his existence.
