Roslander is the book about a couple, Frank and Agatha. They were stranded on an island for five years, where they meet some unusual creaturesa clan of merbeings (mermaids and mermen). They learn to live with the merbeings in harmony. They also learn many other secrets and the history of the merbeings. Agatha keeps a journal of the five years and the information they learn while they are on the island. There are all kinds of adventures and discoveries throughout the book.