Marcus Sedgwick does it again, proving that he is the master of imaginative, engaging literature. There are improbabilities associated with the premise of this book which are discarded in the reader's mind within pages of the beginning. Thereafter, the gripping tale kicks in and it is impossible not to be rooting for the protagonist and her seemingly impossible to achieve quest. But this is not just a tale of adventure, Sedgwick invests his characters with all too human failings and a sympathetic understanding of their needs and aspirations. The study of societal responses to disability is telling, both shameful and uplifting and the result is a read which is highly satisfying. I've awarded four stars but it could so easily have been five.