Charlie is in Edinburgh with his parents, who are acrobats performing at the festival. While there, he discovers a secret tunnel under the city, and a diary which leads him into a search for treasure and a battle with dangers from under the ground. Combining a rich sense of history with Arthurian mythology and a wonderfully exciting adventure story, this is an unputdownable read. Jan Henderson runs ghost tours in Edinburgh and makes frequent appearances as 'ghostly Scotland' expert on Scottish TV. Edinburgh's underground city is opening to the public for the first time this summer.