When he turned around I could see the spread of the feathery green wings that sprouted from his shoulders, beautiful waving wings. I felt as if I were suddenly on a different planet. Part of me wanted to drop to my knees. 'Who are you?' I gasped. The loblolly boy has the gift of flight. He is invisible to most people, apart from the Sensitives; is much coveted by the sinister Collectors; and he has the power to Exchange - to swap identities with others. But the children who choose to Exchange - often to escape very miserable lives - soon realise that to become one of these magical, Peter Pan-like creatures brings complications and dangers they never anticipated.