Jack and his robot buddy, Danny One, set off for the planet Janus to rescue the young King Paul from his conniving uncle.
- ISBN10 0064402169
- ISBN13 9780064402163
- Publish Date 1 March 1988 (first published 1 January 1985)
- Publish Status Out of Print
- Out of Print 19 January 2017
- Publish Country US
- Imprint HarperCollins Publishers
- Format Paperback (US Trade)
- Language English