A pearl spirit maiden from Guanyin's side descends to the mortal world to repay a life-saving kindness from three hundred years ago. She enters an old clam and is caught by the fisherman Chen Binghai, who names her Zhuzhu. Zhuzhu can hear the sounds beneath the sea, locate schools of fish, and avoid hidden reefs. She helps Chen Binghai go from empty nets and mounting debts to overflowing catches, buying a boat, and establishing a fishermen's association. Zhao Dabiao grows jealous and causes trouble, while Li Jingshan of the Tongsheng Trading House in the provincial capital blocks the ice routes and tries to force Chen Binghai to sell Zhuzhu. Refusing to sell his daughter, Chen Binghai guards a coral cave and cultivates pearls in abandoned waters. In the end, he defeats Tongsheng, builds a three-room tiled house, and reunites his family in a life of mutual protection and harmony with the sea.