Marilla, a little mermaid
A young mermaid who sacrifices her life in the ocean to find Prince Adair after seeing his picture in a locket. She suffers terrible pain and loses her beautiful voice in exchange for a human life.
Evelina & Erina
Marilla's older sisters. They enjoy collecting treasures from the human world and are distraught to see their sister's heartbreak when the Prince marries Dana.
Lyr, Lord of the Sea
Lyr is fearful of humans and the threat they pose to his domain. He reluctantly allows Marilla to leave the ocean behind and live a human life, but this comes at a price.
Dillion, the seahorse
Marilla's best friend. Concerned for her, he tries to stop her from entering the human world.
A young prince who, after being saved from a shipwreck, is haunted by a dream-like memory of a beautiful voice.
A young princess, Dana finds the Prince washed up on the shore. The Prince mistakes her for his saviour and they marry.