Sula and her mermaid friends have a chance to sing for Princess Rowena.  The princess is trying to get assistance to help others rebuild after a storm.  Sula learns of a missing singing shell that has the power to cause storms or calm waters.  When her friends become trapped by surging water, Sula decides to try to locate the missing shell.  The text is large and there are many black and white illustrations within the pages.  The story line in rather bland, but young readers who are mermaid fans will probably seek out these Sula books.