Li Guixiang is addicted to playing mahjong. When going out to attend a game, she forgets to turn off the bathtub faucet, causing her grandson An'an to be left alone at home and drown in danger. Her son is lured by gambling friends into a gambling trap and falls into huge debts. Having learned her lesson the hard way, Li Guixiang feigns returning to the gambling den, cleverly collects key evidence such as the scam gang's account books and recordings, stirs up internal conflicts within the gang, assists the police in wiping out the gambling and scam den, and helps victimized elderly people recover their losses. The family resolves their estrangement, says goodbye to the past, and welcomes a solid and happy new life.