Set in the period of the barbarian invasions. Its hero is a young Roman nobleman named Marcus, the son, according to one legend, of the Archangel Michael. Marcus undergoes extraordinary experiences as he searches for meaning and stability in a twilight world where the old gods are dead or dying, but their mysteries still attract, and the new religion is threatened by new barbarisms. Marcus's journeys take him over the empire, from Italy to Greece and Byzantium, to the camp of Alaric the Goth and the wastes of the northern forests, from a Christian monastery to the horde of Attila the Hun. His is a world where everything is possible and nothing solid, a world that is full of danger and mystery, of love and terror, of simple faith and abstruse philosophy, of cruelty, strange perversions, treachery and undaunted courage.