For two hours, the restorer worked alone, the silence broken only by the shuffle of feet outside in the street and the rattle of rising aluminum storefronts. The interruptions began at ten o’clock with the arrival of the renowned Venetian altar cleaner, Adrianna Zinetti. She poked her head around the restorer’s shroud and wished him a pleasant morning. Annoyed, he raised his magnifying visor and peered down over the edge of his platform. Adrianna had positioned herself in such a way that it was impossible to avoid gazing down the front of her blouse at her extraordinary breasts. The restorer nodded solemnly, then watched her slither up her scaffolding with feline assurance. Adrianna knew he was living with another woman, a Jewess from the old ghetto, yet she still flirted with him at every opportunity, as if one more suggestive glance, or one more “accidental” touch, would be the one to topple his defenses. Still, he envied the simplicity with which she viewed the world. Adrianna loved art and Venetian food and being adored by men. Little else mattered to her.

A young restorer called Antonio Politi came next, wearing sunglasses and looking hung over, a rock star arriving for yet another interview he wished to cancel. Antonio did not bother to wish the restorer good morning. Their dislike was mutual. For the Crisostomo project, Antonio had been assigned Sebastiano del Piombo’s main altarpiece. The restorer believed the boy was not ready for the piece, and each evening, before leaving the church, he secretly scaled Antonio’s platform to inspect his work.

Francesco Tiepolo, the chief of the San Giovanni Crisostomo project, was the last to arrive, a shambling, bearded figure, dressed in a flowing white shirt and silk scarf round his thick neck. On the streets of Venice, tourists mistook him for Luciano Pavarotti. Venetians rarely made such a mistake, for Francesco Tiepolo ran the most successful restoration company in the entire Veneto region. Among the Venetian art set, he was an institution.

“Buongiorno,”Tiepolo sang, his cavernous voice echoing high in the central dome. He seized the restorer’s platform with his large hand and gave it one violent shake. The restorer peered over the side like a gargoyle.

“You almost ruined an entire morning’s work, Francesco.”

“That’s why we use isolating varnish.” Tiepolo held up a white paper sack.“Cornetto?”

“Come on up.”

Tiepolo put a foot on the first rung of the scaffolding and pulled himself up. The restorer could hear the aluminum tubing straining under Tiepolo’s enormous weight. Tiepolo opened the sack, handed the restorer an almond cornetto, and took one for himself. Half of it disappeared in one bite. The restorer sat on the edge of the platform with his feet dangling over the side. Tiepolo stood before the altarpiece and examined his work.

“If I didn’t know better, I would have thought old Giovanni slipped in here last night and did the inpainting himself.”

“That’s the idea, Francesco.”

“Yes, but few people have the gifts to actually pull it off.” The rest of the cornetto disappeared into his mouth. He brushed powdered sugar from his beard. “When will it be finished?”

“Three months, maybe four.”

“From my vantage point, three months would be better than four. But heaven forbid I should rush the great Mario Delvecchio. Any travel plans?”

The restorer glared at Tiepolo over the cornetto and slowly shook his head. A year earlier, he had been forced to confess his true name and occupation to Tiepolo. The Italian had preserved that trust by never revealing the information to another soul, though from time to time, when they were alone, he still asked the restorer to speak a few words of Hebrew, just to remind himself that the legendary Mario Delvecchio truly was an Israeli from the Valley of Jezreel named Gabriel Allon.

A sudden downpour hammered on the roof of the church. From atop the platform, high in the apse of the chapel, it sounded like a drum roll. Tiepolo raised his hands toward the heavens in supplication.

“Another storm. God help us. They say the acqua alta could reach five feet. I still haven’t dried out from the last one. I love this place, but even I don’t know how much longer I can take it.”

It had been a particularly difficult season for high water. Venice had flooded more than fifty times, and three months of winter still remained. Gabriel’s house had been inundated so many times that he’d moved everything off the ground floor and was installing a waterproof barrier around his doors and windows.

“You’ll die in Venice, just like Bellini,” Gabriel said. “And I’ll bury you beneath a cypress tree on San Michele, in an enormous crypt befitting a man of your achievements.”

Tiepolo seemed pleased with this image, even though he knew that, like most modern Venetians, he would have to suffer the indignity of a mainland burial.

“And what about you, Mario? Where will you die?”

“With a bit of luck, it will be at the time and place of my own choosing. That’s about the best a man like me can hope for.”

“Just do me one favor.”

“What’s that?”

Tiepolo gazed at the scarred painting. “Finish the altarpiece before you die. You owe it to Giovanni.”

THE FLOOD SIRENS atop the Basilica San Marco cried out a few minutes after four o’clock. Gabriel hurriedly cleaned his brushes and his palette, but by the time he’d descended his scaffolding and crossed the nave to the front portal, the street was already running with several inches of floodwater.

He went back inside. Like most Venetians, he owned several pairs of rubber Wellington boots, which he stored at strategic points in his life, ready to be deployed at a moment’s notice. The pair he kept in the church were his first. They’d been lent to him by Umberto Conti, the master Venetian restorer with whom Gabriel had served his apprenticeship. Gabriel had tried countless times to return them, but Umberto would never take them back. Keep them, Mario, along with the skills I’ve given you. They will serve you well, I promise.

He pulled on Umberto’s faded old boots and cloaked himself in a green waterproof poncho. A moment later he was wading through the shin-deep waters of the Salizzada San Giovanni Crisostomo like an olive-drab ghost. In the Strada Nova, the wooden gangplanks known as passerelle had yet to be laid down by the city’s sanitation workers-a bad sign, Gabriel knew, for it meant the flooding was forecast to be so severe the passerelle would float away.

By the time he reached the Rio Terrà San Leonardo, the water was nearing his boot tops. He turned into an alley, quiet except for the sloshing of the waters, and followed it to a temporary wooden footbridge spanning the Rio di Ghetto Nuovo. A ring of unlit apartment houses loomed before him, notable because they were taller than any others in Venice. He waded through a swamped passageway and emerged into a large square. A pair of bearded yeshiva students crossed his path, tiptoeing across the flooded square toward the synagogue, the fringes of theirtallit katan dangling against their trouser legs. He turned to his left and walked to the doorway at No. 2899. A small brass plaque read COMUNITÀ EBRÀICA DIVENEZIA: JEWISH COMMUNITY OF VENICE. He pressed the bell and was greeted by an old woman’s voice over the intercom.

“It’s Mario.”

“She’s not here.”

“Where is she?”

“Helping out at the bookstore. One of the girls was sick.”

He entered a glass doorway a few paces away and lowered his hood. To his left was the entrance of the ghetto’s modest museum; to the right an inviting little bookstore, warm and brightly lit. A girl with short blond hair was perched on a stool behind the counter, hurriedly cashing out the register before the setting of the sun made it impossible for her to handle money. Her name was Valentina. She smiled at Gabriel and pointed the tip of her pencil toward the large floor-to-ceiling window overlooking the canal. A woman was on her hands and knees, soaking up water that had seeped through the allegedly watertight seals around the glass. She was strikingly beautiful.