At the palace banquet, Guo Tianyi amazed everyone with his acrostic poem, but was publicly humiliated by Wang Shijie, the son of the prime minister of the dynasty: "A man with clay legs is qualified to talk about poetry and books?" Unexpectedly, this scholar who seemed to come from a poor family turned out to be the secret envoy of the Dragon Guard who had been lurking in the court for ten years.
In order to investigate the assassination of the late emperor fifteen years ago, Guo Tianyi moved into the East Palace Courtyard under a secret order and secretly investigated as the prince's companion. However, he accidentally got involved in multiple whirlpools such as the four princes' struggle for the right to inherit the throne, the harem battles, and the border rebellion. What's even more troublesome is that Wang Shijie not only opposes him everywhere, but also covets Su Qinglan, the daughter of the former princess whom Guo Tianyi secretly protects.
In the court, Guo Tianyi solved three unsolved cases in a row with scheming means, winning the recognition of the saint; in the harem, he used his meticulous thinking to resolve the frame-up of the imperial concubine and gained the queen's trust. When all the clues point to the inside of the royal family, a shocking secret emerges - the late emperor was not assassinated, but died of a well-planned baby exchange conspiracy.
And the real prince who was replaced was Guo Tianyi himself.
Now, he not only wants to take back everything that should belong to him, but also uncover a more terrifying truth: someone is using the same method to prepare to subvert the country again...
