In the winding underground tunnels of the Library, the great celestial peacekeeper of the three systems, a terrible secret lies buried. As the daughter of a Library god, Freida has spent her whole life exploring the Library's ever-changing tunnels and communing with the gods. Her unparalleled access makes her unique – and dangerous. When Freida meets Joshua, a mortal boy desperate to save his people, and Nergüi, a Disciple from a persecuted religious minority, Freida is compelled to break ranks with the gods and help them. But in order to do so, she will have to venture deeper into the Library than she has ever known. There she will discover the atrocities of the past, the truth of her origins, and the impossibility of her future… With the world at the brink of war, Freida embarks on a journey to fulfill her destiny, one that pits her against an ancient war god.