It tells the story of Luo Yu, a master of modern agriculture, who traveled through the Tang Dynasty in the first year of Zhenguan and came to prominence after meeting Cheng Yaojin - refining salt to solve the problem of salt shortage in the army, using medical skills to save wounded soldiers, and also carrying high-yielding crop seeds such as potatoes. He acted arbitrarily, causing trouble in court and contradicting the powerful, but he gained the attention of Li Shimin and Queen Changsun, and formed a bond with Princess Changle and Li Chengqian. Faced with the constraints of the court and the obstacles of promoting new crops, Luo Yu used modern thinking to deal with it. While interacting with Cheng Yaojin and others, he worked for people's livelihood. He eventually became a key figure affecting the national destiny of the Tang Dynasty and found value in the prosperous Tang Dynasty.
