Arty and Susy are exploring Heather Grange, an abandoned house with a tragic history. It is now shuttered and deserted. Or is it? ‘The light faded and the hall became dark. It wasn’t so much the lack of light that freaked me - It was the sense of a presence other than my own. Someone watching. And then I heard a sound that unlocked my trance. A soft, echoing whistle.’ A tatty sketchbook. A girl in a blue dress. The half-forgotten memories of an old lady. They are the threads that weave a spine-chilling mystery.