Chen Yuanshan, a laid-off seventh-grade master fitter, loses his job and faces overwhelming financial pressure from his family's school fees and medical bills. Relying on his exceptional fitting skills, he buys damaged precision instruments cheaply from the factory scrap yard, repairs them, and sells them to support his family. However, his former colleague Zhao Zhiqiang and secondhand goods dealer Gao Mingda repeatedly make things difficult for him and try to suppress his business. While collecting discarded items to make a living, he discovers valuable historical materials hidden among old objects, including account books from an established trading house, a bronze postal relay token, a wartime resistance transport map, and classified machine-tool blueprints. Despite tempting offers of large sums of money, he refuses to sell historical artifacts and documents illegally and voluntarily hands them over to the archives to preserve the city's collective memory.