Many years have passed since Gabriel Allon took retribution on those who killed the Israeli athletes at the Munich Olympics. Now he is a master art restorer in Venice. But when one of his fellow agents in that affair is murdered, Gabriel is reactivated by his old mentor, Ari Shamron, to find out why. He discovers that Benjamin had been investigating Pope Pius XII's role in the Holocaust, and apparently was getting too close to the truth. A secret Vatican society known as the Crux Vera is intent on hiding the facts. A powerful Cardinal and his henchmen plan to assassinate the new Pope to keep him from opening the Vatican's secret archives. Gabriel races across the face of Europe, from Venice's Jewish ghetto to Vienna to London to a convent on Lake Garda, and finally to the innermost parts of the Vatican. He is usually just one step ahead of Italian and German police, an assassin known as The Leopard, and even some Israeli agents, as he desperately tries to discover the facts and save the Pope. In the end, it all comes down to a very young nun and a sleepy little orphan boy.
I was reading it about the time that Pope John Paul was in his final illness, and one of the characters in the book is the imaginary pope who follows him.