Lizzy Baxter's life is turned upside down when she moves to Cornwall and discovers that she has a long-lost brother and that their mother is a mermaid. Lizzy soon learns that the tranquil underwater world is ruled by an evil mermaid queen, Taran, who will stop at nothing to complete her power. After a terrifying battle, Taran is one step nearer to her goal. But then she disappears. Lizzy is suspicious. She knows Taran needs the black pearl the key to ultimate power but how is she planning to get it?A thrilling final episode by Louise Cooper, the renowned fantasy writer.