The Caretakers are at war. The Archipelago of Dreams has fallen to the Echthroi, and the link to the Summer Country has been lost. The Keep of Time must be rebuilt, and the secret lies somewhere in Deep Time at the beginnings of the World, when the Summer Country and the Archipelago were one and the same. Fortunately, there is still hope: the Grail child, Rose Dyson, and the new Cartographer Edmund McGee have learned how to map time, and through a precarious balance of travel to the past and the future, they have a chance of repairing the present. Rife with allusions to history’s great literary figures and personalities, from Gilgamesh and Medea to Edgar Allan Poe and H.G. Wells, this absorbing adventure, the sixth in the Imaginarium Geographica series, leads its heroes to a land where all secrets may be found: Known at the beginning of time as the City of Jade, history came to call it Atlantis. And it is there that the Architect of the Keep may have trained the young angel who built the city—an angel named Samaranth.