A long time ago when there were no rivers or lakes, there lived 4 dragons. The long dragon, the yellow dragon, the black dragon and the pearl dragon.
One day, when the dragons were playing, the pearl dragon spotted something and told the others to look at what see saw.
It was an elderly woman praying to the jade emperor to bring rainfall. the dragons then agree to see the Jade Emperor.
When the dragons go to see the Jade Emperor, he is not pleased. but after a while, the Jade Emperor agrees to bring rainfall to the land.
After spraying the clouds with ocean water so the clouds would make rain, the dragons are trapped under a mountain by the mountain god at the Jade Emperor's will. After the dragons are captured however, they turn themselves into rivers in order to continue to help the people.