The story begins in the early 80s with a young widow, "Xiao Gu," raising her three children by running a street-side cooking stall called "Happy Restaurant" in Chinatown. There, she meets Jin, a man who appears honest but is actually a bandit. On their wedding day, Jin's attempt to rob a gold shop is exposed, and he is killed by the police. Before dying, he entrusts Xiao Gu with the care of his son and daughter.
With the philosophy of "whether laughing or crying, it’s all one day—why not laugh?" Xiao Gu positively raises her five children. Her charm brings prosperity to the "Happy Restaurant," and she takes over a coffee shop and market for operations. As life seems to be improving, conflicts over interests and emotions arise among the growing children...
Xiao Gu's eldest son, Kaida, attends medical school; her second son, Kaijie, studies law; and her youngest daughter, Kaqi, attends university—all with promising futures. However, Jin's son and daughter show no interest in education. His son, Jilong, lacks ambition and leads an aimless life; his daughter, Jifeng, dreams only of becoming a TV star and shows no interest in studying. Jilong harbors resentment about his father's death, believing that the family betrayed him and that Xiao Gu prospered from his father's ill-gotten gains. Among them, only Kaqi does not provoke his animosity, and he secretly likes her but dares not express it due to their different statuses. After Kaqi graduates and becomes a journalist with a boyfriend, Jilong feels bitter. The relationship between Jilong and Kaijie is particularly strained, but Jifeng and Kaijie are close friends. Kaijie helps Jifeng attend an acting training class without the family knowing. Tempted by Jifeng's beauty, Kaijie has a physical relationship with her, though he doesn't truly love her. His real goal is Lin Fei, a law student and the only daughter of lawyer Lin Desheng, whose pursuit would guarantee a bright future.
One day, Jifeng is found drowned, and Jilong suspects Kaijie is responsible. This causes a rift between Jilong and the Huang family, leading him down a crooked path. After many twists and turns, he becomes a well-known "Loan King" in the underworld and meets "Rougu Mei," a fiery young woman helping her elderly grandfather sell Bak Kut Teh. After graduating from law school, Kaijie joins the police force and achieves numerous successes. Conflicts with Jilong persist. Kaida knows Jifeng was indeed killed by Kaijie but covers up his crime, feeling guilty and self-blaming, which leads to mental issues preventing him from fulfilling his dream of becoming a doctor and causing his girlfriend to leave him. After graduation, Kaqi becomes a journalist uncovering criminal syndicate misdeeds and learns that Jilong has become a high-ranking figure in the underworld. She hopes he will repent and turn back, but Jilong says he's on a path of no return...
The conflict between Jilong and Kaijie escalates. Jilong is forced to flee to the countryside, while Kaijie hides abroad due to upper-level investigations. Despite Jilong's efforts to find Kaijie and kill him for revenge, he eventually "puts down the sword" and returns to surrender himself to legal justice. For over 20 years, Xiao Gu faces family changes with resilience. She sells all her assets to charity, takes the mentally recovering Kaida to reopen the "Happy Restaurant" sign, and continues living actively, often quoting her famous saying: "Whether laughing or crying, it’s all one day—why not laugh?"