During Mr. Hardy's investigation of a ruthless gang of terrorists, Frank and Joe witness an explosion in the sky near an airborne dirigible owned by Quinn Air Fleet. The young detectives look into a clue that takes them into a new animal park outside Bayport, where they are lured into a trap by an unknown enemy. Problems arise for the park owner as he receives pressure from a competitor and a real-estate firm to sell out. Strange occurrences at the park also frighten the visitors and animals. Frank and Joe take up the case despite fore warnings.
| ISBN: | 9780448089584 |
| Publication date: | 1st June 1978 |
| Author: | Franklin W. Dixon |
| Publisher: | Grosset & Dunlap an imprint of Penguin Young Readers Group |
| Format: | Hardback |
| Pagination: | 180 pages |
| Series: | Hardy Boys Mystery Stories ; 58 |