When he exchanges medallions with the boy who appears to be his double, Dave goes back 800 years in time to medieval Wales.
- ISBN10 0582150434
- ISBN13 9780582150430
- Publish Date 20 September 1971 (first published 1 January 1971)
- Publish Status Out of Print
- Out of Print 18 October 2003
- Publish Country GB
- Imprint Prentice Hall Press
- Format Hardcover
- Pages 194
- Language English