In 755 AD, on the eve of the Anshi Rebellion, Li Yan, a Ph. D. Student in physics, accidentally traveled through time and became the concubine of Emperor Xuanzong of the Tang Dynasty, the Yongwang Li Lin. He originally wanted to stay away from the whirlpool of power, but he found that the Tang Dynasty was different from the historical records: there were dragon veins whispering under Chang'an City, runes looming in the water of the Yellow River, and foreign tribes at the border could control strange celestial phenomena. When An Lushan's rebels broke through Tongguan, Li Yan had to arm the Tang army with modern knowledge: gunpowder improvements, epidemic prevention systems, economic tactics... But he gradually discovered that behind all these changes, there was actually a "historical revision organization" that spanned a thousand years. While fighting against the rebels and pursuing the truth, Li Yan brought modern science into the era of cold weapons. In the cracks of history, he tried to reverse the fate of a dynasty, but he did not know that he had already become a key piece in a larger chess game.
