Keep moving. Stay in the light. Don't look back.The planet Nivalis turns so slowly that only a narrow band of land is ever warmed by its sun. This moving zone-called the Bright Spot-is the last refuge for life. Everything outside it has frozen into desolation. Centuries ago, civilization thrived in both light and shadow-until the darkness turned deadly. No one knows why. Few dare to ask.Caelius marches with The Brightest, a caravan devoted to following the light's path around the world. Faithful. Fearful. Unyielding. But when the caravan suddenly stops moving, they find uneasy refuge in the shadow of the ancient city of Solace. When one friend disappears, Caelius begins to see the cracks in their beliefs-and in himself. Violence follows. So does doubt.With humanity unraveling around him, Caelius must face a terrible choice: cling to who he was, become what he's feared, or rise as something entirely new.