Liu Chenglin, a vegetable deliveryman, marries Su Mei, a widow, only to discover after moving in that she is burdened with over a hundred thousand yuan in debt, a bedridden mother-in-law, and a six-year-old son. On the day of their engagement, their landlord kicks down the door demanding rent, while relatives try to persuade him to call off the engagement. Instead, he puts every last bit of his five years of savings—20,000 yuan—into this family. With a seven-day deadline and three pairs of hands in the household, he cuts half the items from the menu and starts delivering hot steamed buns to construction sites on his tricycle, growing from 80 orders to 130. He gets greedy, makes mistakes with delivery times, and faces competitors undercutting his prices, but eventually learns that 'money you cannot afford to earn is a ticking bomb.' A year later, every IOU has been stamped 'Paid in Full,' and the child finally calls him 'Dad' at the school gate.