The film focuses on a mother (Chen Yanyan) burdened by guilt after abandoning her newborn daughter in a long lane 17 years earlier, so that she could adopt a son to fulfil the traditional belief that only a male heir could continue the family line. However, when her adopted son (King Hu) becomes a disappointment, the mother’s regret deepens. On her deathbed, she confesses her secret to her husband (Wang Yin), who resolves to find their lost daughter.