Murong Chengyan, a doctor of modern agriculture, woke up and became the son of a criminal official during the Zhenguan period of the Tang Dynasty. His family was impoverished and had no food to eat. Facing the impending famine, he looked at the "poisons" everywhere in the back mountains and smiled. Starting from offering potatoes to solve the famine, fighting aristocratic families, promoting agriculture, opening up commerce, and strengthening military armaments. When the entire Tang Dynasty became different because of his appearance, Li Shimin looked at the map and fell into deep thought: "Chengyan, you said the earth is round, can our Tang Dynasty's fleet fight back from the other side?"
