Lu Qingchuan, an auto mechanic, keeps a repair shop running with his exceptional technical skills. Yet his boss, Chen Jianshan, who is also his uncle by marriage, gives him only 80 yuan in profit-sharing, claiming the business performed poorly. After seeing through Chen's greed and manipulation, Lu angrily quits and establishes himself at a new shop through his solid reputation and superb skills. Chen repeatedly resorts to underhanded tactics, suppression, and slander, but Lu fights back with the evidence he has accumulated. Ultimately, Chen's business collapses because he profits from cutting corners and using substandard materials, and he suffers the consequences of his own actions. Years later, Chen, now down on his luck, repents. Lu shows him some leniency, proving that business depends on skill, not scheming.