After the rebels abandon her, Aubrey doubts her abilities more than ever. She failed to close the Abyss and lost the person she was beginning to love. Desperate to prove herself, Aubrey enters the demon realm to save him, only to trigger a new disaster. She releases the Four Horsemen of the Apocalypse. These angels are uncompromising in their purpose; to massacre humanity. Aubrey alone has an immunity to match the angels, but it isn't enough. She is faced with making a pact with a demon, or worse, the rebel leader. Aubrey must decide or lose those she cares about.