Once upon a time, Gabriel Allon, one of the best intelligence officers, tried to retire, but in the end was forced to return to his previous job. And now one can only dream of peace and quiet... Intelligence became aware of the assassination attempt, which “Al- Qaeda" is preparing for the Pope himself. Gabriel is ordered to immediately go to the Vatican and prevent a terrorist attack at all costs. He begins the hunt for the criminals - but all his efforts are unsuccessful. Gradually Allon comes to the only possible conclusion: there is an agent of terrorists in the Vatican, supplying them with secret information .But who is he? How to find him? There is less and less time before the planned assassination attempt, and intelligence officers still cannot find the traitor...