Twenty-five years after the Archagnel Gabriel led an army of lower angels in the "Extinction War" against humans, the survivors have retreated to fortified cities such as Vega where they struggle to exist and rebuild society among political turmoil, internal power struggles and the ever present threat of danger from the angels. Soldier Alex Lannon, a rogue operative with a rebellious streak and a dangerously close relationship with the daughter of Vega's ruler and the Archangel Michael, the only angel to side with humans in the war, are among the only hopes humans have of surviving and perhaps winning the war.