12 year-old Ryan (Caitlin Carmichael) and her dad (Jerry O'Connell) pack up their belongings and move to a seemingly quiet fishing town to live with grandfather Art (Barry Bostwick). Eager to get to know his granddaughter more, Art tells Ryan local stories and myths of mermaids that live along their shores, but who have never been seen. Although her dad is a non-believer, Ryan is ready to believe in the magic hidden in her new home, and whilst exploring the local coves and watching a pod of playful dolphins, she meets Coral. Coral and Ryan become fast friends and it is soon clear that Coral is much more than an average girl, but in fact one of the mermaids that grandfather Art had told Ryan all about. The truth brings the two girls closer and soon they are working together to save the town as they uncover a powerful secret in this modern day fairy tale.