Alona and Perlas (both played by Louise delos Reyes) are born with unusual features-one is born with gills behind her ears and the other with a mermaid's tail. Worried that neighbors might be surprised by their strange features, their mother, Marissa (played by Mickey Ferriols), decides to move along with them to an isolated island. Due to unfortunate circumstances, Alona and Perlas have to live separately. Living with her mother, Perlas works in an ocean park while Alona lives as a princess within the confines of the waters-the kingdom of Sirenadia ruled by Queen Arowana (played by Angelika dela Cruz). Kevin (played by Aljur Abrenica) is a handsome and rich son of Susanna (played by Lotlot de Leon) , whom the twins fall in love with. Kevin manages the family company where he meets Perlas. As they start to develop feelings for each other, Susana learns that Perlas is the daughter of Marissa, who they consider as the cause of her brother's death. Meanwhile, Alona also finds love with ...