Zhao Shanhe, a seasoned auto mechanic, stands firm on his repair principles and refuses to conceal vehicle safety hazards for profit. When his apprentice, Gao Kai, is tempted by financial gain and conspires with a car dealer to falsify information and frame him, Zhao relies on his technical expertise, evidence, and the law to uncover the truth. By upholding the spirit of craftsmanship and protecting consumers' rights, he promotes the professional conviction that workers must respect life, act honestly, and obey the law, illustrating the patriotic warmth of an ordinary worker who remains true to his principles.