Jiang Ahe, a young woman from a fishing village, discovers Qinglin, a pregnant dragon trapped in an iron-chain fishing net during low tide. Unable to bear watching the dragon and her unborn offspring being butchered for their pearls and gallbladders, Ahe cuts the nets that sustain the entire village and saves Qinglin in front of everyone, earning the wrath of Cui Guangyun, the leader of the Cao Gang. The gang exploits the people through predatory debt contracts and secretly operates a deadly sluice gate to drown indebted laborers. Ahe's older brother, who has been missing for ten years, is one of its victims. Joining forces with He Lian, a conscientious accountant, and the villagers, Ahe enlists the dragon clan's help to have a hundred flood dragons blockade the Cao River. They brave the dragon's lair, break through the deadly sluice gate, rescue the trapped people, and present all the evidence of Cui Guangyun's bribery and murder. In the end, the villain is brought to justice, the unjust debt contracts are abolished, humans and dragons reconcile, and peace returns to the rivers.