In order to find inspiration, Hanfu designer Chi Xiaoyu came to Dengdao to collect folk songs and met the owner of the B&B Gui Haixi and her brother Gui Haiyao. In the B&B, Xiaoyu often encountered strange events such as the figure of a mermaid in the swimming pool. Gui Haiyao, who performed mermaids for a living, turned out to be the prince of the mermaid tribe and his lifesaver when he was a child! In order to save Chi Xiaoyu, Gui Haiyao lost the mermaid pearl, and his memory and strength gradually declined. It was not until the reunion that he gradually recovered his memories that had been sealed for many years. At the same time, a mysterious female tycoon has been secretly observing all this. She is immortal and seems to be related to the legendary Dongnu Kingdom, which feeds on mermaids. The female tycoon brought her men to Haideng Island. With her arrival, an unknown storm will be set off again...