Chen Yu, a tidal harvester, is betrayed by his girlfriend Liu Manyun and Han Tianhu, the son of a local tyrant. Pushed into the Ghost Reef waters, he drifts onto a deserted island and saves Yue Ji, the Mermaid Queen, who gifts him a Water-Repelling Pearl. From then on, he moves underwater as easily as on land and gathers countless deep-sea treasures. He returns to the village to expose the truth, grows rich with the pearl, cuts off greedy relatives, crushes villains, fights the fishing overlords, and uncovers what really happened to his parents years ago. In the end, he becomes the king of the deep sea and finds true love with Xu Yanyu.
