Asia Minor, sixth century: After several centuries of conflict with the early Christian church, the Manichaeans, a heretical sect, vanish from the historical record.

Bosnia, 1992: Ian Pearse, a young American relief worker destined for the priesthood, has his faith tested by the horrors of war, but is jolted from his despair by a passionate affair with a Croatian woman named Petra.

Rome, present day: Father Pearse, now a researcher at the Vatican Library, comes into possession of an ancient scroll after the mysterious death of one Vatican priest and the disappearance of another. His scholar’s curiosity aroused, he has the document translated by an old friend in Rome. He is stunned to learn that the scroll