Iron and Magic

Hugh d'Ambray, Warlord of the Builder of Towers, served only one man — and now his immortal, nearly omnipotent master has cast him aside. Hugh is a shadow of the warrior he was, but the Iron Dogs, the soldiers who would follow him anywhere, are being hunted, and he has to find the strength to save them.

Elara Harper commands a walled castle in Kentucky and the people sheltering inside it, and she is a creature who by rights should not exist. She has resources and no army; Hugh has an army and nothing else. To convince both of their peoples that the alliance is real, they marry — a marriage of convenience between two people who despise each other.

Iron and Magic is the first book of Ilona Andrews' Iron Covenant, set in the same post-apocalyptic world as the Kate Daniels series, where technology and magic take turns winning.