[Suspense reasoning + alternate history + time travel + 1v1bg direction]
Shortly after the new emperor ascended the throne, a headless corpse was found in a field outside the imperial city. Due to the seriousness of the case, the emperor ordered the Secretary of the Criminal Office to assist the Secretary of the Taili Office in investigating the case.
At the same time, modern man Lu Yijiu was forced to bind a system and travel to this world to conquer it. The system asked him to work hard to get into the Tailifu Department to advance the mission, otherwise everyone would explode together. Forced by the threat, Lu Yijiu had no choice but to work hard and successfully entered with the help of luck and props.
Until the Daogen dismemberment case occurred, the system issued a mission [to prevent the villain from becoming emperor]. As soon as the mission was assigned, Lu Yijiu began to think about who the villain would be. It was better to find out and stop him now than not be able to defeat him later.
After the matter was settled, Liu Qinghe saw that he was very talented and asked His Majesty the Emperor to keep him by his side and train him well. Lu Yijiu just wanted to say please let him go! No!
As the investigation deepened, Lu Yijiu found that his boss Liu Qinghe was acting more and more like a villain, but he didn't seem to think so in his heart...
Warning: I am following a pseudo-archaic style of suspense reasoning, an imaginary world view, and the official positions are fictitious. The author is an idiot. Please forgive me for the poor writing. I guess it is B (whispering), or more.
Concept: In countless twists and turns, the protagonist finally discovers that he has been kept in the dark by the villain, which indirectly leads to the death of his assistant, and finally completes the system mission.