In the sea, it is not just the sea animal who lives there. There is also a half-fish half-human who lives in the ocean. The humans on the dry land call them mermaids/mermen. The humans only know them as mythical creatures in a book. Nobody believes that they exist. These beings live in the sea peacefully for so many centuries. They have a tradition that when a certain mermaid or merman comes at the age of 20, they are allowed to enter the dry land for six years. Along with that tradition, there is a rule that they must follow at all costs or else death will be their end; they are not allowed to be together with a human. That is the rule that their King Neptune set ten centuries ago. Celena Cordelia Atlantia, the fourth princess of the sea, has come to the dry land, but she is not excited for even one bit. Where human lives are the last place, she wanted to stay. However, during her stay in the human land, she met a cold-hearted CEO, and since then, her life in the human land has never been the same. He, Ethan Everborn, the business industry king, never cared for anything except for business. But when he met Celena, everything change. All he could think about is her. Come and join Ethan and Celena as they overcome the challenges in their life.