On the mermaid's route to finding the second Snow Diamond they discover that a baby polar bear and walrus have gone missing from their families and Katie and her friends vow to help find them. In gratitude, the chief walrus helps the mermaids to unravel the riddle which Mantora has devised to stall them in their quest for the next Snow Diamond.
- ISBN10 1599903377
- ISBN13 9781599903378
- Publish Date 3 February 2009 (first published 5 March 2007)
- Publish Status Out of Print
- Out of Print 27 May 2021
- Publish Country US
- Imprint Bloomsbury U.S.A. Children's Books
- Format Paperback (US Trade)
- Pages 96
- Language English