This is a legend about "turning things around and becoming an emperor through the ages".
The modern man Liu He became the famous deposed emperor in history, and he was deposed after 27 days on the throne. He just wanted to lie down and save his life: he pretended to be ill and did not go to court, planted vegetables in the imperial garden, studied food, and drew drawings of toys... But every bad thing he did was thought up by the supporters and opponents as unfathomable imperial ideas - canceling the morning court was to retreat into progress, growing sweet potatoes to understand the sentiment of the people, painting a roller coaster to design new weapons, casually saying "the weather is nice and suitable for posting books" turned out to be a grand ceremony to respect Confucianism.
The agricultural revolution came out of lying down, laziness and stealing became military myths, and preparations to run away were regarded as luring the enemy to penetrate deeper. Sweet Potato Diplomacy quelled the war, the Heavenly Book's edict triggered seven interpretations, and the Nonsense Diary was regarded as the supreme classic of the emperor's mind.
From the time when he was on the verge of death and deposing the emperor to serving as a guest all over the world, he only did three things: talk less, see more, and do nothing. At the end of the story, by the pond of Jiangnan Manor, the retired old man put away his fishing rod, listened to the children in the distance reciting his "Sacred Instructions", and yawned - What are you going to eat tonight?