During the Yongle period of the Ming Dynasty, Shen Yanqiu, the head of the Shuntian Prefecture in the capital, was famous for his keen observation and unconventional investigation methods, but he often offended the powerful because he was too upright. Once, he took over a case of the mysterious death of an official, and the half-piece of jade pendant held in the deceased's hand became the only clue. At the same time, Su Qingwan, a folk wonder girl who is proficient in the secret language of the agency, came to the capital with her other half of the jade pendant to find her missing brother, and accidentally got involved in the same case with Shen Yanqiu. As the investigation deepened, they discovered that a mysterious organization spanning the government and the public was involved behind the murder, and the code on the jade pendant was the key to unlocking the secrets of the organization. The two went from distrusting each other to tacit cooperation. Amidst the flashes of swords and intrigues, the two got closer to the truth step by step, and gradually uncovered the connection between the disappearance of Su Qingwan's brother and the organization.
