Lin Kuai, a courier who was on the verge of death, suddenly saw everyone's "life countdown" in front of his eyes. In order to extend his lifespan of only three days, he was forced to sign a strange labor contract and become a temporary worker for the underworld's "Yin Yang Express". His mission is to shuttle between modern cities and ancient tombs to deliver special "obsession packages" to the souls of historical celebrities stranded in the world: delivering a takeout order to Qin Shihuang, searching for the lost sword of a general who died in battle, and delivering the unsent love letter of Concubine Yang to her reincarnation.
