The searing conclusion of the thrilling epic fantasy trilogy that saw a young girl trained by an arcane order of nuns grow into the fiercest of warriors... They came against her as a child. Now they face the woman.  The ice is advancing, the Corridor narrowing, and the empire is under siege from the Scithrowl in the east and the Durns in the west. Everywhere, the emperor’s armies are in retreat.  Nona Grey faces the final challenges that must be overcome if she is to become a full sister in the order of her choice. But it seems unlikely that she and her friends will have time to earn a nun’s habit before war is on their doorstep.  Even a warrior like Nona cannot hope to turn the tide of war. The shiphearts offer strength that she might use to protect those she loves, but it’s a power that corrupts. A final battle is coming in which she will be torn between friends, unable to save them all. A battle in which her own demons will try to unmake her.  A battle in which hearts will be broken, lovers lost, thrones burned.