Chen Jianguo, a warehouse supervisor, intercepted 37 unauthorized shipments over ten years, earning the company's deep trust. After his efforts prevented Deputy General Manager Zhao Tiancheng from secretly shipping out copper, Zhao held a grudge and deliberately arranged a pay cut to force Chen out, installing Zheng Hao as his replacement. With the gatekeeper gone, Zhao shut down the surveillance cameras, removed the double locks, and conspired with accomplices to steal 240 tons of copper over six months. Chen Jianguo instructed Zhou Dahai to take photographs and Li Yang to contact Wang Li to gather evidence. In court, three notebooks, 117 photographs, and delivery records brought Zhao Tiancheng down, earning him a twelve-year prison sentence. With his name finally cleared, Chen turned down a lucrative offer from his former employer and joined a new company, determined to pass on his experience in protecting the warehouse.