The princesses at Emerald Castle have an art lesson on the beach one day, and Princess Millie can't believe her eyes when she sees a mermaid out at sea! The nasty twins Diamonde and Gruella refuse to believe that mermaids exist, but they are taught a lesson that they will never forget!

This book features in the following series: The Tiara Club, The Tiara Club At Emerald Castle .

There are 80 pages in this book. This book was published 2008 by Hachette Children's Group .

Sarah Gibb is the talent behind The Bridesmaid's Diary, that has become an international success story. She lives in London. Vivian French is a well-known author who has written over 150 books for children.