During the Yongle period of the Ming Dynasty, bizarre murders occurred one after another in Shuntian Prefecture in the capital. The deceased all held a strange rouge button in their hands, and the circumstances of their death were exactly the same as an unsolved case ten years ago. Shen Jinghong, a rising star in Jinyiwei, has emerged with his keen observation and strong logical reasoning ability. However, during the investigation process, he repeatedly encounters the mysterious woman Su Ningshuang and "cuts her off". Su Ningshuang is burdened with an old family grudge. In order to find out the truth behind her father's involvement in the unsolved case, she relies on her superb disguise skills and familiarity with the world to secretly investigate the clues. The two initially tried to undermine each other, "falling in love and killing each other", but were later forced to join forces to solve a series of murders. In the process of searching for the truth, they not only had to face the obstruction of the court forces and the conspiracy of Jianghu organizations, but also uncovered the shocking secrets hidden behind the unsolved cases ten years ago. As the investigation deepened, they discovered that all the cases were related to a missing "Map of Mountains and Rivers". Behind this map, there was actually a conspiracy that could shake the foundation of the Ming Dynasty, and the fate of the two people was tightly tied together.
