Retired chief shield machine designer Song Mancang went incognito to Shanghai to stay with his daughter, only to be mistaken by his son-in-law's family as an ordinary migrant worker. Hiding his true identity, he relied on his top-tier craftsmanship to resolve multiple crises for a small factory. He Zhenbang, a rival who had previously plagiarized his achievements, secretly plotted against him and maliciously smeared his late wife. Song Mancang used solid evidence to expose the entire conspiracy and clear the deceased's name. Afterwards, he supported a practical small factory, passed down artisan skills, returned to his ancestral homeland in the Central Plains, and contributed to his hometown's water conservancy tunnel project, interpreting a touching story of a great nation's craftsman who is indifferent to fame and wealth.