An ancient loan made by Pope Pius VIII wreaks havoc in the present. The new religious conspiracy thriller featuring Cal Donovan. While browsing the Vatican libraries, Harvard professor Cal Donovan uncovers a secret that could bankrupt the Catholic church. Unearthing evidence of a 200-year-old loan which the Vatican owes to a Jewish bank, Cal deduces that, with centuries of interest behind it, the sum now amounts to a crippling 25 billion Euros. With the future of the Vatican at stake, Pope Celestine asks Cal to intercede with the Sassoon family to whom the sum is owed. Thus Cal finds himself drawn into the tangled affairs of the wealthy yet dysfunctional Sassoons. With eye-watering sums of money involved and the Vatican facing bankruptcy, everyone has their own agenda. Who can be trusted? If Cal isn't careful, he'll find more than his own life in danger.