THE ISLAND ADVENTURE.

Book info: THE ISLAND ADVENTURE. (Hardcover, 192 pages – Armada, 1967) – Armada, 1967. Language: Eng.

For Philip, Dinah, Lucy-Ann and Jack, the holiday in Cornwall is everything they'd hope for - until they begin to realize that something very sinister is taking place on the mysterious Isle of Gloom. But they're not prepared for the dangerous adventure that awaits them in the abandoned copper mines and secret tunnels beneath the sea.