On Liushao Street in Linjiang City, Zhang Xiaomo, the proprietor of Zhang's Eatery, makes an honest living with the old abacus left to her by her father. But the wealthy merchant Qian Wanguan tries to take over the entire street by raising rents and cutting off supplies. Zhang Xiaomo unites the local shopkeepers and residents to form a mutual-support merchants' association to protect themselves. She then encounters Lu Zhao, an imperial censor secretly inspecting the area in disguise. Together, they gather evidence and fight against the forces of corrupt officials and unscrupulous merchants. With the support of the people and the evidence in their account books, they bring the greedy merchant down. Zhang Xiaomo leads the local residents in establishing a cooperative trading association, successfully protecting Liushao Street and upholding justice in the marketplace.