The story tells the story of a generation of "grain people" with conscience. The male protagonist Gao Yuan and Qu Zhengping are close friends. More than 30 years later, Gao Yuan returns to his hometown as the new director of the Grain Department. Shortly after taking office, he received a mysterious "anonymous letter" reporting that the grain depot was actually empty, and the spearhead was directed at Qu Zhengping, who was then the deputy governor. Gao Yuan, who was determined to thoroughly investigate the truth, was interfered with and tracked from all sides. Why was there an empty warehouse in the Red Flag Grain Depot? Who is the mysterious whistleblower? One difficult mystery after another hit Gao Yuan. The two male protagonists, Gao Yuan and Qu Zhengping, are played by Li Youbin and Zhang Zhizhong, who are known as "professional policemen" respectively. When talking about this play, Li Youbin said frankly: "Acting should not start from events, but from the feelings of the characters. Acting is not a competition, but a process of understanding roles, society, and problems." Zhang Zhizhong, who has always been known as a "tough guy", plays Qu Zhengping in "The Grain Man of Heaven and Earth". Due to their different political views, he and his good friend Gao Yuan parted ways and became irreconcilable opponents. With rich acting experience, he will struggle between emotions and greed, and portray the characters' personalities realistically and movingly. This is a long-form TV series with the grain industry as the background, which pays close attention to "grain security" and "agriculture, rural areas and farmers" issues, and enthusiastically praises the high sense of responsibility and selfless dedication of "grain people" to society. The teenage years of the protagonists Gao Yuan, Qu Zhengping and Fang Jie were spent in the "three-year natural disaster". With grain as the bond, Gao Yuan, a descendant of farmers, and Qu Zhengping, the son of the county party secretary, formed a life-and-death friendship; also with grain as the bond, Gao Yuan also developed a vague relationship with Fang Jie, the daughter of an agricultural expert. Nearly forty years have passed, and Qu Zhengping is now the vice governor in charge of agriculture and grain, and Fang Jie is now a senior engineer at the Provincial Grain Inspection Institute. She has been divorced from Gao Yuan for seven years. On this day, Qu Zhengping, who had just divorced his ex-wife Ye Wen, was about to make public his love relationship with Fang Jie, which had evolved from their teenage friendship. Gao Yuan, who was far away in Beijing, suddenly returned to Beijing as the new director of the Grain Department. The story officially began. In fact, Gao Yuan did not come back just to rekindle a relationship. He was a man who had a deep memory of the Great Famine, had been working in grain and regarded grain as his life. So when he found an empty warehouse in his hometown of Heji City that had been emptied by "grain rats" shortly after he came back to take office, he decided to carry out a "four clearings and four inspections" aimed at finding out the family's financial situation and establishing a sound grain reserve safety system. However, Qu Zhengping was promoted to vice governor because of his outstanding performance as the director of the Grain Department. In particular, the Heji Grain Depot was the red flag model depot set up by Qu Zhengping! As a result, a conflict of friendship arose between the two sides. Why the warehouse was emptied and where the funds obtained from the empty warehouse went also became a mystery for the time being.