Raphael and Elena are experiencing their first ever year of true peace. No war. No horrors of archangelic power. No nightmares given flesh. Until.the earth beneath the Refuge begins to tremble, endangering not only angelkind's precious and fragile young, but the very place that has held their most innocent safe for eons. Amid the chaos, Elena's father suffers a violent heart attack that threatens to extinguish their last chance to heal the bonds between them and make sense of the ruins of their agonizing shared history. Even as Elena battles grief, Raphael is torn from her side by the sudden disappearance of an archangel.

But worse yet is to come. An Ancestor, an angel unlike any other, stirs from his Sleep to warn the Cadre of a darkness so terrible that it causes empires to fall and civilizations to vanish. This time, even the Cadre itself may not be able to stop a ticking clock that is counting down at frightening speed.