Watermelon farmer Liu Dashan is cheated out of part of his harvest through malicious deductions. Refusing to sign an unfair agreement, he takes his daughter to seek other buyers and helps fellow villagers sell their watermelons together. Faced with canceled orders, disputes over transportation costs, and arguments about old debts, he finds himself questioned instead. Liu Dashan voluntarily admits his past negligence and insists on checking the accounts against evidence, prompting the refund of unjustified deductions and reforms to the rules. In the end, he not only repays his 12,000 yuan debt in full but also upholds his dignity and justice through transparent, open transactions.