An ordinary girl discovers an unusual gift from her parents. From her mother she is a human, and from her father she is a mermaid. And as soon as she gets into the water, her tail grows. Now she has friends in the underwater world, she goes to school there, learns to be a real mermaid. Only she always gets involved in stories with her best friend. Now they are “floating” onto a huge abandoned ship. And then they suddenly find themselves on their boat in the middle of the ocean, where even mermaids cannot swim to the shore. And then Emily sees a mysterious castle in her dream...