During the Dazhong period of the late Tang Dynasty, a canal boat loaded with official provisions sank unexpectedly on the Bian River, and no boatman survived. It happened that Shen Yan, a poor scholar who was on his way to Beijing to take the exam, passed by here. Because he was proficient in arithmetic and good at observation, he was unexpectedly spotted by Li Zhan, the censor who was ordered to investigate the case, and was temporarily included in the investigation team. At first, everyone characterized the case as a "natural disaster." However, when Shen Yan inspected the scene, he found man-made chiseling marks on the ship's deck and special tokens hidden among the shipwright's relics.
During the investigation, Shen Yan and Li Zhan encountered repeated obstacles: local officials passed the buck in every possible way, the water transportation yamen deliberately concealed their case, and even mysterious Jianghu forces secretly obstructed their investigation. They were hunted down many times. As the investigation deepened, Shen Yan gradually discovered that this water transport case was not an isolated incident. Behind it was a power game between the forces of the vassal town headed by Jiedushi Wang Duo and the party of Prime Minister Li Deyu - the official grain was robbed to fund the vassal town's expansion of armaments, while the shipwreck was to destroy evidence.
Shen Yan originally wanted to focus on scientific research and change his own destiny, but during the investigation, he witnessed the suffering of the people at the bottom and the arrogance of corrupt officials, and his inner sense of morality was completely awakened. With his wisdom, he repeatedly saw through conspiracies and formed an alliance with Li Zhan, the chivalrous female bodyguard Su Ningshuang and others. Under the dual pressure of the court and the Jianghu, he got closer to the truth step by step. However, when the truth surfaced, he discovered that his most respected teacher was also involved. On one side was justice, on the other was kindness. Shen Yan was caught in a dilemma... In the end, he used his meager power to leverage the overall situation and revealed a shocking conspiracy. Although he missed the scientific examination, he became the "folk blue sky" protecting the people.
