Zi Hao lives in a seaside town and returns to Hong Kong, so, he finds mysterious girl Xiao Yi and began to take care of Xiao Yi’s life. The crew of the ocean ship where Zi Hao’s father was located disappeared. After experiencing the pain of bereavement, Zi Hao came out of the haze under the care of Xiao Yi, and the two were together. But the good times did not last long. A mysterious middle-aged man named Lao Jin came to Hong Kong and revealed the true identity of Xiao Yi - Xiao Yi turned out to be a mermaid! Can Zi Hao accept Xiao Yi’s identity, and can Xiao Yi keep her race secret?