Xu Zhihe, a vegetable farmer, has eighty mu of greenhouse crops that she cannot sell. Vegetable wholesalers join forces to force down prices, cold storage facilities refuse to store her produce, and her loan falls due tomorrow. Unexpectedly, the ancient well in her backyard connects to Zhenbei City in ancient times, where General Lu Chengxiao has been besieged by the Hu army and cut off from food for thirty days. She sends her unsold vegetables to save the city, and in return receives an ancestral jade artifact that sells for three million yuan, allowing her to repay her loan. She then buys up all the unsold vegetables in the entire county. During a night raid, she supplies flashlights, searchlights, and fireworks to repel the enemy. She also helps Lu infiltrate the enemy camp and obtain evidence of a treacherous minister's secret correspondence with the enemy, leading to a decisive victory and the lifting of the siege. She establishes long-term grain supply and trade agreements and is honored with the title of Military Supply Officer. At last, she turns her desperate situation around.