For Philip, Dinah, Lucy-Ann and Jack, the holiday in Cornwall is everything theyd hope for - until they begin to realize that something very sinister is taking place on the mysterious Isle of Gloom. But theyre not prepared for the dangerous adventure that awaits them in the abandoned copper mines and secret tunnels beneath the sea. Paperback , 192 pages Published June 1st 2000 by Pan Macmillan (first published 1944)