When Sophie discovers a mysterious crystal cave while she and her friends are playing hide-and-seek, no one believes her and she tries to prove its existence to them.
- ISBN10 1481499858
- ISBN13 9781481499859
- Publish Date 24 October 2017
- Publish Status Active
- Publish Country US
- Publisher Simon & Schuster
- Imprint Little Simon
- Format Paperback (US Trade)
- Pages 128
- Language English