Chang'an in the twelfth year of the Zhenguan era becomes the setting for a mechanical fantasy spanning a thousand years. Li Yan, a modern mechanical engineer, arrives in the body of a craftsman in the flourishing Tang dynasty, carrying a jade Azure Dragon pendant engraved with a quantum star chart. As he measures Zhuque Avenue with calipers and rebuilds Taiye Lake with concrete, he has no idea that he is slowly turning the gears of a colossal mechanism encompassing all of China. From the bearings of the curved-shaft plow to the gears of the armillary sphere, from the coded signals of Dunhuang's beacon towers to the steam core of Luoyang's underground palace, the entire Tang dynasty is becoming a finely engineered machine for rewriting history.
