When doppelgangers start appearing in Oxford, Union Jack agents Ignatius and Indigo find themselves on another cosmic quest, one they didn't set out to investigate.Drawn into the search for the elusive and dangerous Book of Shadows, they find themselves traveling across the cosmos once again, racing against other versions of themselves, and visiting the Oracle to be given prophecies of terrible destruction that will engulf the cosmos in darkness. Only these two heroes-or their doubles-can open the book, which would lead to dreadful consequences for themselves, the world and the whole of creation. The agents must outwit their own mirror souls and invade the impregnable Administorium, which holds the answers they need but also fearsome enemies of both the Union Jacks and the entire cosmos. In this quest, Ignatius and Indigo must protect not only England and the Empire, but the world and the cosmos.