Grace loves living in the tropical village of Cala Sands, it has a gorgeous beach and the sun always shines. She especially likes to swim with the magical sea ponies that live in the warm, clear waters around the bay. Grace wishes more than anything that she could talk to the ponies - especially the pretty pony with the sparkling eyes and rainbow tail!When Sophy and Maya arrive and tell Grace that magical creatures all over the kingdom are in terrible danger, Grace knows she has to protect the precious sea ponies. Cruel Lady Cavendish is sailing out into the ocean to catch them in a huge net, so Grace, Maya and Sophy stow away on her ship. But will their rescue plan work? And will Grace ever get her magical speaking stone and be able to speak to her favourite sea pony?