Allon is recovering from a grueling showdown with a Palestinian master terrorist, when a figure from his past arrives in Jerusalem. Monsignor Luigi Donati is the private secretary to His Holiness Pope Paul VII, and a man as ruthless as he is intelligent. Now, however, he has come to seek Allon's help. A young Swiss guard has been found dead in St. Peter's Basilica, and although Donati has allowed the official inquiry to determine that it is suicide, his instinct tells him that it is murder - and that his master is in grave danger. He has trusted Allon in the past, and he is the only man he trusts now.