Nigel. Sons of Ymre, #3

Long ago, a mad god almost destroyed the world. And he is still out there, waiting. Cass Tierney knows what lives in the darkness; her small group of bogey-hunters clings to the edge of starvation, depending on her strange talents to fight monsters the daylight world doesn't want to know about. Her group is smart, dedicated-and losing, while a greater danger stalks ever closer. Nigel is a Father of the Sons: cold, rigorous, impeccably controlled.
Sent to clear a city beyond the Continental Divide, he expects nothing good. Before long, his team is burnt out of shelter and chased westward. Then, he finds the impossible-a lone lirai, capable of near-miracles, one of the priceless few he's sworn to protect. Cass has no reason to trust her kidnapper; Nigel has little time for explanations. If they can just get past the Rockies they might have a chance at survival, but as casualties mount it becomes clear the Mad God has always planned otherwise.
The ruthless, ancient being will use all his monstrous hordes to hunt her down; Nigel will do anything to save her. The only advantage they have is each other. Especially after night falls.