When the Hardy Boys set out to solve the mystery of their missing chums, they discover a gang hide-out in a cave on an island along the way.
- ISBN10 1557091471
- ISBN13 9781557091475
- Publish Date 1 April 1996 (first published August 1974)
- Publish Status Out of Stock
- Imprint Applewood Books
- Format Hardcover
- Pages 214
- Language English