Zeroth Variable

In the third year of Zhenguan, Chen Xuance sneaked into Fang Xuanling's shogunate as a recorder of affairs for a poor family. For three months, he relied on the voice in his head, which called himself "Lingshu", to deduce military situations and foresee variables, and gained a place in the court. He thought it was a golden finger, a privilege reserved for time travellers—until the voice sounded on its own one night: "Experimental group, the first round of deduction begins. Variable implantation is completed. Expected divergence point: Zhenguan four years." Only then did he understand that the Tang Dynasty was not history, but a laboratory. The Lingshu is not a system, but an observer. And he is not the only variable. Enemy proton Pei Yuanzhou carved a network of markers in Chang'an, connecting all those who tried to escape from the script; Emperor Li Shimin received an encrypted signal from the "upper level" and found that he was just a data point in the experimental report; Liu Yunli, a river and lake luther master, saw another self in the string sounds - a woman from modern times with the same name as her. They all have planned endings. The only question is: who wrote the script, and why did they leave a variable that could deny execution? Chen Xuance chose not to break or obey. He chooses to understand.