In the first Moon Stealer book, Sir Edgar and the children are on a quest to find the Silver Bough. Left in the keeping of Sir Hadwyn, the Earl of Rosslyn until his death of Pneumonia in the winter of 2011, they discover his tomb with a riddle engraved around the edge of his shield, directing them towards the Bough.
The Bough was made by a druid called Arawyn Claremont. He cut a branch from the Elm tree that stood in his garden and carved it into a curved flute. He then performed strong magic on it. To most people the Bough would look like nothing more than a plain and dull wooden flute, but when held in the right hands, it would turn to silver and play the most magical music. The music would enchant and possess certain animals, as well as provide Arawyn an entrance into the Faerie World.
Once the Silver Bough has chosen its owner, anyone else that attempts to use it will become tormented by the screams and curses of the lost souls that are trapped between the two worlds.