“The Holy Father won’t hear of it.” Donati joined Gabriel at the window. “Besides, it’s too late. The guests have started to arrive.”

THEY SETTLED HIM in a tiny cell with a sooty window overlooking the Belvedere Courtyard and gave him a boyish-looking ex-carabiniere named Luca Angelli to fetch the files. He limited his search to laypersons only. Even Gabriel, a man of boundless suspicion, could not imagine a scenario under which a Catholic priest could be recruited, knowingly or unwittingly, to the cause of al-Qaeda. He also struck from his list members of the Swiss Guard and Vigilanza. The ranks of the Vigilanza were filled largely by former officers of the Carabinieri and Polizia di Stato. As for the Swiss Guard, they were drawn exclusively from Catholic families in Switzerland and most came from the German- and French-speaking cantons in the mountainous heart of the country, hardly a stronghold of Islamic extremism.

He started with the lay employees of the Vatican city-state itself. To limit the parameters of his search he reviewed only the files of those who had been hired in the previous five years. That alone took him nearly thirty minutes. When he was finished he set aside a half dozen files for further evaluation-a clerk in the Vatican pharmacy, a gardener, two stock boys in the Annona, a janitor in the Vatican museum, and a woman who worked in one of the Vatican gift shops-and gave the rest back to Angelli.

The next files to arrive were for the lay employees attached to various congregations of the Roman Curia. The congregations were the approximate equivalent of government ministries and dealt with central areas of Church governance, such as doctrine, faith, the clergy, saints, and Catholic education. Each congregation was led by a cardinal, and each cardinal had several bishops and monsignori beneath him. Gabriel reviewed the files for the clerical and support staff of each of the nine congregations and, finding nothing of interest, gave them back to Angelli.

“What’s left?”

“The pontifical commissions and councils,” said Angelli. “And the other offices.”

“Other offices?”

“The Administration of the Patrimony of the Holy See, the Prefecture of the Economic Affairs of the Holy See-”

“I get it,” Gabriel said. “How many files?”

Angelli held up his hands to indicate that the pile was well over a foot high. Gabriel looked at his watch: 11:20 …

“Bring them.”

ANGELLI STARTED WITH the pontifical commissions. Gabriel pulled two more files for further review, a consultant to the Commission for Sacred Archaeology, and an Argentine scholar attached to the Pontifical Commission for Latin America. He gave the rest back to Angelli and looked at his watch: 11:45 … He’d promised Donati that he would stand guard over the Pope in the square during the general audience at noon. He had time for only a few more files.

“Skip the financial departments,” Gabriel said. “Bring me the files for the pontifical councils.”

Angelli returned a moment later with a six-inch stack of manila folders. Gabriel reviewed them in the order Angelli handed them over. The Pontifical Council for the Laity…The Pontifical Council for Promoting Christian Unity…The Pontifical Council for the Family…The Pontifical Council for Justice and Peace…The Pontifical Council for the Pastoral Care of Migrants and Itinerant People…The Pontifical Council for Legislative Texts…

The Pontifical Council for Inter-religious Dialogue…

Gabriel held up his hand. He had found what he was looking for.

HE READ FOR a moment, then looked up sharply. “Does this man really have access to the Vatican?”

Angelli bent his thin body at the waist and peered over Gabriel’s shoulder. “Professor Ibrahim el-Banna? He’s been here for more than a year now.”

“Doing what?”

“He’s a member of a special commission searching for ways to improve relations between the Christian and Islamic worlds. There are twelve members in all, an ecumenical team of six Christian scholars and six Muslim scholars representing the various Islamic sects and schools of Islamic law. Ibrahim el-Banna is a professor of Islamic jurisprudence at Al-Azhar University in Cairo. He’s also among the most respected scholars of the Hanafi school of Islamic law in the world. Hanafi is predominant among-”

“Sunni Muslims,” Gabriel said, pointedly finishing Angelli’s sentence for him. “Don’t you know that Al-Azhar is a hotbed of Islamic militancy? It’s been thoroughly penetrated by the forces of al-Qaeda and the Muslim Brotherhood.”

“It is also one of the oldest and most prestigious schools of Islamic theology and law in the world. Professor el-Banna was chosen for the position because of his moderate views. He’s met several times with the Holy Father himself. On two occasions they were alone together.”

“Where does the commission meet?”

“Professor el-Banna has an office in a building near the Piazza Santa Marta, not far from the Arch of Bells.”

Gabriel looked at his watch: 11:55… There was no way to talk to Donati. He would be downstairs with the Pope by now, preparing to enter the square. He thought of the instructions he’d given him the previous night in the Via Belvedere. Make a general nuisance of yourself. If you see a problem, address it. He got to his feet and looked at Angelli.

“I’d like to have a word with the imam.”

Angelli hesitated. “The initiative is very important to the Holy Father. If you level an accusation against Professor el-Banna without just cause, he will take great offense and the commission’s work will be placed in jeopardy.”

“Better an irate imam than a dead Pope. What’s the quickest way to the Piazza Santa Marta?”

“We’ll take the shortcut,” Angelli said. “Through the Basilica.”

THEY SLIPPED THROUGH the passage from the Scala Regia into the Chapel of the Blessed Sacrament, then hurried diagonally across the vast nave. Beneath the Monument to Alexander VII was a doorway leading into the Piazza Santa Marta. As they stepped outside into the bright sunlight, a roar of wild applause rose from St. Peter’s Square. The Pope had arrived for the General Audience. Angelli led Gabriel across the small piazza and into a gloomy-looking Baroque office building. In the lobby a nun sat motionless behind a reception table. She gave Gabriel and Angelli a disapproving look as they burst inside.

“Ibrahim el-Banna,” said Luca Angelli without elaboration.

The nun blinked twice rapidly. “Room four-twelve.”

They mounted the stairs, Angelli leading the way, Gabriel at his heels. When another swell of applause rose from the square, Gabriel gave Angelli a jab in the kidneys, and the Vatican security man began taking the steps two at a time. When they arrived at Room 412 they found the door was closed. Gabriel reached for the latch, but Angelli stayed his hand and knocked firmly but politely.

“Professor el-Banna? Professor el-Banna? Are you there?”

Greeted by silence, Gabriel pushed Angelli aside and examined the ancient lock. With the slender metal pick in his wallet he could have coaxed it open in a matter of seconds, but another roar of approval from the square reminded him there wasn’t time. He seized hold of the latch with both hands and drove his shoulder into the door. It held fast. He threw his body against the door a second time, then a third. On the fourth attempt, Angelli joined him. The wood of the doorjamb splintered, and they tumbled inside.

The room was empty. Not just empty, thought Gabriel. Abandoned. There were no books or files, no pens or loose papers. Just a single lettersized envelope, positioned in the precise center of the desk. Angelli reached for the light switch, but Gabriel shouted at him not to touch it, then pushed the Italian back into the corridor. He drew a pen from his coat pocket and used it as a probe to examine the density of the envelope’s contents. When he was reasonably certain it contained nothing but paper, he picked it up and carefully lifted the flap. Inside was a single sheet, folded in thirds. Handwritten, Arabic script: