In Republican-era Beiping, Chen Tiechi, a master roast duck chef, refuses to use diseased ducks, determined to uphold his conscience. However, his apprentice, Li Shunzi, betrays him, crippling his right hand and leaving him to make a living at a street stall near Tianqiao. To pay for his wife Xiuniang's treatment for tuberculosis, Chen unlocks a left-handed knife technique that has been sealed away for twenty-five years. With his honest craftsmanship, he builds a reputation for himself. Meanwhile, his treacherous former apprentice amasses a fortune selling tainted roast duck. But when poisoned meat is served at a warlord's birthday banquet, the villains end up suffering the consequences of their own wickedness. Chen refuses to use his knife to hurt others, choosing instead to earn his living through honest cooking. In the end, he and his wife open a small roast duck shop, preserving the dignity of the world through their dedication to craftsmanship, while every fragrant oven of roast duck reveals the good and evil in people's hearts.