Manlius is a 5th C Roman patrician living in Provence who has studied with the wise, reclusive Sophia. He writes his understanding of her teaching in his essay, 'Dream of Scipio,' which trades on an essay by the great Roman orator, Cicero. Sensing that the Empire is gravely threatened, he makes a pact with barbarians, sells out his neighbors, slays his adopted son, and becomes a bishop of the Christian religion, which he has long despised. Late in this ruthless and doomed attempt to salvage what he values most in his world, Sophia makes it clear that he has misunderstood her teaching.

Olivier is an astonishingly gifted 14th century Provencal poet whose intolerant father tries to stifle his love of letters, among which is Manlius's 'Dream'; his father destroys the manuscript, but Olivier recopies it from memory. As plague advances on their region, Olivier finds a mentor in the high churchman, Ceccani, who is bent on keeping the papacy in Avignon. He plans to destroy Jews as symbolic expiation for plague, widely construed to be a form of divine punishment. Olivier befriends a Jewish scholar and falls in love with his beautiful heretic servant.

The 'Dream' and the imprisonment of his friends lead Olivier to question and then betray his mentor. Either because of his efforts to save them, or for his role in a murder, he is mutilated--his tongue and hands cut off to rob him of speech and writing. The brutal mutilation appears early in the book--it is not fully explained until the end.

Julien is a French historian who has studied the poet, Olivier, and the rendition of Manlius' manuscript. He finds solace in his erudition as his county falls to the Nazi occupation. An old school friend who is a collaborator, gives him work as a censor and tolerates Julien's Jewish lover, the artist Julia. In the end, Julien is forced to choose between saving either another school friend in the Resistance or Julia. He chooses Julia, looses her anyway, and commits suicide in a vain attempt to warn his friend.