In this transformed post--apocalyptic future an army of lower angels, assembled by the archangel Gabriel, has waged a war of possession against mankind. The archangel Michael, turning against his own kind, has chosen to side with humanity against Gabriel. Season 2 sees Alex and Michael facing new threats, including a mysterious city called New Delphi and the machinations of higher angels. The season also explores the consequences of a past war and the angels' motivations for fighting.