During the Ming Dynasty, the escort Shen Qing was ordered to escort the birthday gift, but was attacked by a person who was poisoned by smoke and poison on the way. The birthday gift was robbed, and the emperor was furious, and ordered the secret service to investigate the matter thoroughly. In order to clear the injustice of colluding with the robbers, Shen Qing, who escaped from death, was forced to join the Royal Secret Service. He formed a partner with Wang Tu Niu, who was disguised as a man and was determined to redress her father's injustice, and vowed to find out the truth of the matter. The two of them kept making fun of each other during the crisis-ridden investigation process, saving the prince, making antidotes, and a series of magical operations, making the investigation journey full of laughter. Can this pair of happy enemies finally resolve the many crises? Can the growing relationship between the two wait for the clouds to clear and the moon to shine?