After failing his university entrance exam, Lin Qingshan's family is suddenly struck by misfortune. Just when he is at his wit's end, a black-and-tan dog with four eyes suddenly wanders into his home, carrying an old bamboo tag that once belonged to his grandfather around its neck. Hei Bao, an unusually intelligent dog with an almost human understanding, leads him to uncover his grandfather's old aquaculture notes and an ordinary-looking flowing-water fish trap. Together, they reveal the secret of a muddy pond at the village entrance that everyone has despised for decades. When a creditor demands that he surrender the pond to settle his family's debt, Lin Qingshan firmly refuses: 'I'll lease this pond myself!' Nobody knows that this abandoned pond, which everyone has avoided for years, is about to become the golden road to his comeback, supporting his entire family and leading the whole village toward prosperity.