The son of the Dragon King (a ruler-god of the sea) was caught by a fisherman while taking the form of a fish. Being stuck on land, he was unable to transform back into his dragon form. His father, despite being a mighty Dragon King, was unable to do anything while his son was on land. Distressed, the son called out to all of Heaven and Earth.
Hearing his cry, Quan Yin quickly sent her disciple to recover the fish and gave him all the money she had. The fish at this point was about to be sold in the market. It was causing quite a stir as it was alive hours after being caught. This drew a much larger crowd than usual at the market. Many people decided that this prodigious situation meant that eating the fish would grant them immortality, and so all present wanted to buy the fish. Soon a bidding war started, and Quan Yin’s disciple was easily outbid.
He begged the fish seller to spare the life of the fish. The crowd, now angry at someone so daring, was about to chase him away from the fish when Quan Yin projected her voice from far away, saying “A life should definitely belong to one who tries to save it, not one who tries to take it.”
The crowd realizing their shameful actions and desire, dispersed. The fish was brought back to Guan Yin, who promptly returned it to the sea. There the fish transformed back to a dragon and returned home.
But the story does not end here. As a reward for Quan Yin’s help saving his son, the Dragon King sent his daughter, a girl called Lung Nue (“dragon girl”), to present to Quan Yin the ‘Pearl of Light’. The ‘Pearl of Light’ was a precious jewel owned by the Dragon King that shines constantly for all eternity.