After the stunning events of The Clockwork Ghost, Tess, Theo, and Jaime don't know what to think about their legacy-both past and present. They have only one choice: to follow the Old York Cipher to the end. Doing so reveals the plans for a machine invented over 150 years ago but never built. Its purpose is a mystery, but Tess, Theo, and Jaime know that they must construct it. Doing so, however, will have massive repurcussions and will launch the...