In the autumn of the second year of Zhenguan, Li Yan, a graduate student in the Department of Archeology, traveled back to the early Tang Dynasty due to a laboratory explosion, and his soul passed through the body of Li Chengsi, an orphan from a poor family. The original owner was imprisoned for secretly possessing fragments of oracle bones from the previous dynasty. After resurrecting his body, Li Yan used modern chemical knowledge to identify the composition of pyrite in the fragments and helped the county magistrate crack down on the private mining case. As a result, he was recruited as an aide by Yun Ye, the head of the Chang'an Ministry of Industry.
Li Yan discovered this hidden mystery of the Tang Dynasty: the pattern of the Turkic wolf fang pendant and the jade pendant of Empress Wu De coincided with the star map, and there was a miniature steam engine pattern in the murals of the Zhaoling Underground Palace. He improved the Quyuan plow based on "Tiangong Kaiwu", which greatly increased Guanzhong's grain output by 30%. However, he was impeached by the nobles for "transgressing the etiquette system". In order to prove his innocence, Li Yan restored Zhuge Liannu at the Tai Chi Palace night banquet, but the magnet mechanism of the Wolf Fang Pendant was triggered, revealing that there was another secret behind the Xuanwu Gate incident twenty years ago - the gap in Li Shimin's sword exactly matched the titanium alloy powder left in Li Yan's laboratory.
As the investigation deepened, Li Yan discovered that the fragments of "The Analects of Confucius" in the memory of the original owner were actually code books, recording the super-era technology discovered by Li Jing during his Northern Expedition. When Li Yan tried to use electrolysis to purify copper ore, he was suddenly assassinated by the Guanlong Group. On his way to escape, he met Princess Pingyang who was living among the people. The two cracked the code of the Wolf Fang Falling Star Map and discovered that the Zhaoling Underground Palace actually contained the Armillary Sphere built by the first generation Si Tianjian, and that Li Yan's time travel was actually related to the "Yinghuo Shouxin" astronomical phenomenon observed by the warlock Li Chunfeng thirty years ago...
