S hortly after three o’clock the next morning the apartment shook with an explosive clap of thunder.

Gabriel lay in bed for another hour, listening to the rain lashing against the windows overlooking the Grand Canal, until the first stirrings of a caffeine headache sent him into the kitchen in search of coffee.

He carried his first cup to his studio and drank it while working on the Florigerio.

Chiara poked her head through the doorway a few minutes after six.

“You’re supposed to be wearing a mask when working with those awful solvents.”

“I forgot.”

“That’s because you have no brain cells left.”

Chiara walked over to Gabriel’s worktable. The three sketches lay side by side, arranged in order of execution. She reached for the unmarked manila envelope instead.

“I wouldn’t, if I were you.”

“What’s inside?”

“Three X-rays and a photograph you don’t want to see.”

Chiara removed only the frontal X-ray and placed it next to the sketches. “With all due respect,” she said after a moment, “I don’t see the resemblance.”

“You’re obviously not looking at it the right way.”

“It could be anyone.”

“It isn’t.”

By eight o’clock the streets and squares of San Polo were awash with the floodwaters of a minor acqua alta .

Clad in oilskin coats and rubber boots, Gabriel and Chiara escorted the children to school, then waded over to the Campo dei Frari.

As they walked through the door of Bar Dogale, Paolo automatically placed two cappuccinos on the counter along with a basket of warm cornetti .

Gabriel reciprocated by handing the barman his telefonino .

“Do you recognize her?”

“Should I?”

“She was here about two and a half weeks ago. It was a Monday afternoon. You waited on her.”

“If you say so, Signore Allon.”

Gabriel glanced at the security camera above the bar. “Does that thing work?”

“When it feels like it.”

“What about the camera outside?”

Paolo shrugged. “Sometimes.”

“Can we check the memory?”

“Is it important?”

“It might be.”

The barman led Gabriel and Chiara through a cluttered storage room to an office the size of a closet. Gabriel recited the exact time and date that he had seen the young woman, and Paolo entered the information into the computer. The shot from the interior camera appeared instantly on the screen.

“We were sitting outside,” said Gabriel.

Paolo clicked the mouse once, and the shot changed to the exterior view.

The arrangement of the figures was as Gabriel remembered.

He was seated, as usual, with his back to the front of the café.

Irene was seated to his left, and Raphael was directly opposite.

The young woman occupied the table to Gabriel’s right.

She, too, was facing the campo , which meant that her back was turned to the camera.

“Can you rewind it ten minutes, please?”

Paolo did as Gabriel asked, then set the scene into motion. Both tables were now unoccupied. Three minutes went by before the first of the four figures entered the shot.

“Pause it, please.”

The mouse clicked, the image froze.

“Dear God,” whispered Chiara.

Gabriel held his phone next to the computer screen. The resemblance between the subject of his sketch and the woman in the surveillance video was uncanny.

Chiara played devil’s advocate. “It still doesn’t prove—”

“I agree,” replied Gabriel, cutting her off.

Then he asked Paolo to advance the recording to 3:45 p.m. Gabriel and the children had left by then, but the woman remained at her table until four fifteen, when she laid a few coins atop the bill and departed.

Paolo appeared a moment later to collect the empty coffee cup and the money.

“Now do you remember her?” asked Gabriel.

“Vaguely.”

“Did she say anything to you?”

“She bade me a pleasant day and asked for a cappuccino.”

“In Italian?”

Paolo nodded.

“What was her accent like?”

“It might have been British.”

At Gabriel’s request, Paolo increased the playback speed of the video.

Four customers hurried out of the café like characters in a silent movie, then three more arrived.

One was a tall woman with short dark hair.

She wore white Capri-length trousers, flat-soled shoes, and a dark blue cotton blazer.

Her handbag and single piece of carry-on luggage were matching and costly.

Her sunglasses were large and fashionable.

She removed them before lowering herself into the same chair where Gabriel had been sitting earlier.

Paolo took the woman’s order and delivered it in record time.

“British?” asked Gabriel.

“Definitely.”

“It looks to me as though she came directly from the airport.”

“She said she was meeting someone.”

“Did anyone join her?”

“I don’t think so. But we should probably watch the video, just to be sure.”

They reviewed it at the maximum playback speed. Paolo’s recollection proved accurate.

“Back it up to four twenty-eight,” said Gabriel. “And play it at the normal speed.”

Paolo did as Gabriel asked, and they watched as the woman approached Bar Dogale, towing her carry-on luggage over the paving stones of the campo . At the instant she removed her sunglasses, Gabriel said, “Pause it, please.”

The mouse clicked, the image froze.

Gabriel looked at Chiara and asked, “Do you recognize her?”

“Should I?”

Gabriel found a photograph of the woman online. Then he enlarged the image and held his phone next to the computer screen. “How about now?”

“Impossible,” whispered Chiara.

“Unlikely,” said Gabriel. “But not impossible. ”

***

Admittedly Gabriel should have phoned Luca Rossetti and Colonel Baggio and told them of his suspicions.

Instead he tossed a change of clothing into an overnight bag and headed for the airport.

As luck would have it, there was a business-class seat available on the eleven o’clock British Airways flight to London.

He waited until he had cleared passport control at Heathrow before ringing Amelia March of ARTnews magazine.

His call went straight to voicemail. He left a brief message, and she called him back straightaway.

“When and where?” she asked.

“You tell me.”

“There’s a little coffeehouse on the Portobello Road near George Orwell’s old cottage.”

“Half past two?”

“See you then.”

The small terrace house at 22 Portobello Road had not in fact been Orwell’s; he had lodged there during the winter of 1927 after resigning his position with the Indian Imperial Police.

Gabriel arrived at the coffeehouse on the opposite side of the road fifteen minutes early and sat down at a table in the garden.

Amelia appeared at the stroke of two thirty.

She was clutching the same designer handbag and, despite the gray English skies overhead, wearing the same pair of sunglasses.

She placed them on the tabletop and regarded Gabriel with a mixture of curiosity and apprehension.

“Are you angry with me?” she asked at last.

“Why on earth would I be angry with you?”

“The article.”

“Oh, that,” replied Gabriel.

The article in question had been occasioned by Gabriel’s role in the recovery and restoration of Self-Portrait with Bandaged Ear by Vincent van Gogh, which had been stolen from the Courtauld Gallery in a daring smash-and-grab robbery more than a decade earlier.

Laudatory in tone, the story had referred to him as one of the most accomplished and sought-after art conservators in the world.

It had also confirmed what many in the gossipy art trade already suspected—that he had spent nearly the entirety of his remarkable career living under an assumed identity forged by a clandestine division of Israel’s secret intelligence service.

He had retired from the service after spending five tumultuous years as its director-general.

With the exception of a single operation against the Russians, he had managed to make a clean break with his past. Amelia March, though she did not know it, had played a supporting role in one of his better operations.

“Should I have asked you for a comment?” she asked.

“Isn’t that the way it usually works in your business?”

“Would you have spoken to me?”

“Don’t be ridiculous.”

She smiled. “Once a spy, always a spy. Isn’t that what they say?”

“I’m not a spy, Amelia. I am the director of the paintings department at the Tiepolo Restoration Company in Venice.”

“Is that all?”

“In my spare time, I sometimes help the police solve art-related crimes.”

“Are you working on anything interesting now?”

“A murder investigation, actually.” Gabriel handed over his phone. On the screen was a photograph of his forensic sketch. “I found her in the waters near San Giorgio Maggiore. Thus far, the Italian police haven’t been able to identify her. I was hoping you might know who she was.”

Amelia looked up from the phone. “Why me?”

“Because you were supposed to meet her two weeks ago at a little place called Bar Dogale in the Campo dei Frari. And by the time you finally arrived, she was gone.”

“How do you know that?”

“Swipe to the next image.”

Amelia did as he asked, then frowned. “Once a spy, always a spy. Isn’t that what they say, Mr. Allon?”

“I’m not a spy, Amelia. I’m an art restorer, and I just happen to live in the neighborhood.”