Mermaid Curse: The Golden Circlet by Louise Cooper
Puffin Books ISBN 9780141322285
With the terrifying Tullor safely behind glass at the Sealife Centre, and no news of the evil mermaid Queen Taran, Lizzy almost believes that her troubles are over. But she can't help thinking that it's not like Taran to give up. Follow the plot to gain power as it unfolds in a race against time.