Professor Ha-Ha has based his Sneaky Secret Submarine on the side of a loch deep in Scotland. The only problem is the old lady who lives in the castle. She is not part of his fiendish plans. When strange noises and ghostly appearances begin, Sherlock Hound and Dr Whatsup investigate.

The Case of the Howling Armour 2002, Scholastic, London

ISBN-13: 9780439994460