The impoverished Granny Lin rescues a dying golden retriever named A Fu on a snowy night. This spiritual dog carries its own karma buff of good and evil: treating it kindly brings golden light and family prosperity, while evil deeds trigger black light retaliation and self-inflicted consequences. The Lin family previously relied only on a small soy milk stall to scrape by. Using its keen sense of smell, A Fu repeatedly resolves the harassments and framings by Wu Guilan, Wu Meijuan, and local thugs, helps the Lin family find a leader's lost official document, and secures a state-run pilot storefront. Xiuxiu's pastry-making skills are also discovered, leading them to break through pastry competitions and open a large restaurant. Villains repeatedly steal the dog, poison it, and commit arson, but suffer retribution every time. After enduring severe injuries and abduction, A Fu still protects the whole family, achieving a mutual redemption between the loyal Lin family and the lucky dog