Yu Shan transmigrates to the Tang dynasty as a displaced refugee, and from the start, he is branded the source of a plague.
He saves an entire village with modern epidemic-prevention knowledge, only for the county magistrate to call him a demon and throw him in prison.
There, he meets a fallen crown prince and uses statistics to predict a locust plague, helping the prince regain the emperor’s favor.
When plague breaks out in Chang’an, he draws a map of quarantine zones and astonishes the Imperial Medical Bureau with alcohol disinfection.
As An Lushan’s rebel forces besiege the capital, Yu Shan offers a gunpowder formula that turns the tide of battle.
Empress Wu Zetian secretly tries to recruit him, while Chancellor Li Linfu lays a deadly trap.
Yu Shan smiles faintly in court. “I seek neither power nor dominion over the world.”
He unfurls a map of the world. “Your Majesty, the true battlefield lies among the stars and across the seas.”
