As a heavy rain warning approaches, grandmother Sun Xiu'e casually makes up a lie about gathering herbs in order to go play mahjong. Four-year-old Miaomiao takes it literally, ventures alone into the mountains amid the rain, and narrowly escapes losing her life to a flash flood. Although her parents pull out all stops in a search and rescue to bring the child back safely, Miaomiao is left with severe psychological trauma. The family draws clear boundaries in their interactions, and Sun Xiu'e undergoes a profound self-examination, breaking her bad habit of casually lying. After going through numerous twists and turns, she learns to keep her promises, and the family clears up their misunderstandings, understands the value of sincerity and trustworthiness, and welcomes a long-overdue reconciliation.