To raise money for her seriously ill daughter's medical expenses, Xu Qin, an Eastern domestic helper, accidentally becomes a legendary boiler repair master in a small town after recalling her father's advice that repairing boilers requires looking, listening, smelling, and questioning. When a local repair company reports her for working without a license, Xu Qin immediately signs a life-or-death challenge to compete in boiler repairs, accepting the consequences if she loses. From the mayor's antique boiler to industrial furnaces in factories, and finally to Odin's Heart, a nuclear-grade national treasure that has left all of Europe helpless, she diagnoses every problem by listening to the sounds and rhythms of the machinery, effortlessly humiliating engineers who pride themselves on their expertise. With a five-million-yuan contract and industry giants scrambling to learn from her, even the rivals who once wanted to send her to prison now line up to call her Master.