For three hundred years, humanity has lived beneath the Cinder-Sky-an artificial ceiling of ash and darkness that blots out the sun. The Council of Eternal Light harvests human souls to power the machinery that keeps civilization alive, dissolving millions into silver Ichor.
Thorne was once the Council's most feared Inquisitor. For twenty years, he hunted enemies of the state without mercy-until the Council took his daughter.
Seraphina possesses a unique resonance that makes her the key to the Great Recalibration-a ritual that will make the Council's control eternal. To save her, Thorne must become everything he once destroyed: a rebel armed with a blade called Silence, leading desperate allies through the Grey Marches, the Ironwood Thicket, and into the Obsidian Spire itself.
But the closer he gets, the more he discovers: the sun was never dying. The Cinder-Sky was always a prison.