Veteran technician Lu Yuanshan works through the night to repair a broken production line, saving the factory from massive losses. But Supervisor Zhao exploits a technicality in the regulations to publicly fine him 5,000 yuan. Deeply disappointed, Lu decides to do nothing beyond his assigned duties and leave punctually at the end of every shift. Meanwhile, Zhao Jun secretly alters equipment settings and steals components to cause malfunctions, hoping to frame Lu while earning hefty kickbacks. However, Lu has already installed surveillance cameras and preserved the complete evidence. When Manager Han from headquarters arrives, the truth comes to light, and Zhao Jun is taken away for investigation. The unreasonable fine system is abolished, and Lu Yuanshan is temporarily put in charge of workshop production. He introduces fair new rules, finally ensuring that frontline workers receive the justice they deserve.