No Ordinary Girl (H20, Bk. 1)

When best friends, Cleo, Emma and Rikki find themselves accidentally stranded on a mysterious island something very strange happens. While swimming through an eerie underwater channel, the moon has a magical effect on the water changing the three girls forever. One by one the three friends discover that when they come into contact with water they grow a fishtail and become mermaids! Cleo, Emma and Rikki just want to be normal teenage girls and live normal lives, but as they start to come to terms with their new tails, not to mention their magical powers over H20, they begin to realize that they may never be normal again!