It isn't old age or a disease. He is found hanging in a bathroom while on an official visit to New York City.
All signs point to a suicide and NYPD detective Donnie Beecher is put in charge of the investigation. It's the last assignment he wants. Because of his tragic past, he has no love for the Catholic Church. His marriage is falling apart, his teenage daughter is getting mixed up with the bad crowd.
But soon clues start piling up. What if the Pope was assassinated?
In Vatican City, young and idealistic Father O'Dwyer is beginning to wonder the same thing. Why are the cardinals around him so secretive? Why do they keep whispering about the mysterious San Marino letter?
With his superiors breathing down his neck for a swift resolution, Beecher teams up with Officer Emma Aldridge, a former nun. Failure means not just an end to his career but a shift of power in international relations which could lead to war. Together, they will need to find out what really happened to the Pope.