The woman’s knock was tepid. Instantly the violin fell silent.

“Who goes there?” asked a voice within.

“Herr Klemp has arrived, Frau Rolfe.”

“Please show him in. And then go away.”

Gabriel opened the door and went inside. Anna sat before her dressing table, the Guarneri beneath her chin. The garnet-colored evening gown she wore was shimmering and strapless. Her catlike eyes were fixed on the reflection in the lighted mirror.

“As much as I would like to be kissed by you, I will insist that you somehow restrain yourself. It took several hours of intense effort to get me looking like this.” With her bow she indicated a chair. “Sit, peasant. Speak only when spoken to.”

Anna laid the bow on the strings of the Guarneri and, closing her eyes, played a silken E-minor arpeggio over three octaves. She had played the same simple exercise for hours on end during the six months and fourteen days they had lived together at her villa on Portugal’s Costa de Prata. It was Gabriel, after first stuffing his possessions into a duffel bag, who had ended the relationship. The lines he recited that day were shopworn but entirely accurate. It was his fault, not hers. It was too soon, he wasn’t ready. Tempestuous Anna had endured his performance with uncharacteristic forbearance before finally hurling a ceramic vase at his head and declaring she never wished to speak to him again.

Within a few short months she had wed. The marriage ended with a spectacular divorce, as did her second. There followed a succession of highly publicized affairs and liaisons, always with rich and famous men, each more disastrous than the last. During a recent visit to Venice she had made it clear that Gabriel was to blame for her tragic plight. If only he had married her, had toured the world with her while she basked in the adulation of her fans, she would have been spared a lifetime of romantic misfortune. It occurred to Gabriel, as he sat in Anna’s dressing room, that this was the life she had imagined for them. She was not about to allow the evening to go to waste.

Her bow went still. “Did you have a chance to talk to Simon? He’s quite anxious to meet you.”

“Why would Sir Simon Rattle want to meet lowly Johannes Klemp?”

“Because Sir Simon knows Herr Klemp’s real name.”

“You didn’t.”

“I might have, yes.”

She played the opening melody of the concerto’s andante second movement. It sent a chill, like a charge of electricity, down the length of Gabriel’s spine, as she had known it would. He nevertheless adopted an expression of mild boredom.

“That bad?” she asked.

“Dreadful.”

Frowning, she lit a Gitane in violation of the concert hall’s strict no-smoking policy. “You made quite a splash in London last week.”

“You noticed?”

“It was rather hard to miss. But why the silly pseudonym tonight?”

“I’m afraid that Gabriel Allon can’t be seen with Anna Rolfe in public.”

“Whyever not?”

“Because he needs Anna’s help. And he doesn’t want his target to know that they are acquainted.”

“We were more than acquaintances, my love. Much more.”

“It was a long time ago, Anna.”

“Yes,” she said, contemplating her reflection in the mirror. “I was young and beautiful then. And now . . .”

“You’re no less beautiful.”

“I’d be careful, Gabriel. I can be quite irresistible when I want to be.” She played the same passage from the concerto’s second movement. “Better?”

“A little.”

She took a pull at her cigarette, then crushed it out. “So what do you require of me this time? Another dreary fundraiser or something a bit more interesting?”

“The latter,” said Gabriel.

“No Russians, I hope.”

“We should probably talk about this after your performance.”

“As it happens, I’m free for dinner.”

“A marvelous idea.”

“But if we can’t be seen together in public, our options are somewhat limited. In fact,” said Anna playfully, “it seems to me that the only place where we can be assured of absolute privacy is my suite at the Mandarin Oriental.”

“Will you be able to control yourself?”

“Unlikely.”

There was a knock at the door.

“What is it now?” Anna demanded to know.

“Ten minutes, Frau Rolfe.”

She looked at Gabriel. “You’re free to wait here, if you like.”

“And miss your performance?” Gabriel rose to his feet and draped his coat over his arm. “I wouldn’t dream of it.”

“What time shall I expect you?”

“You tell me.”

“Stay for the Beethoven. It will give me a chance to change into something a bit more comfortable.” She lifted her check to be kissed. “You have my permission.”

“Somehow I’ll resist,” said Gabriel, and went out.

Alone in her dressing room, Anna laid her bow upon the strings of the Guarneri and played a G-major scale in broken thirds. “Don’t smile,” she said to the woman in the looking glass. “You never play well when you’re happy.”

*  *  *

The seat to which the young escort led Gabriel was in the first row, slightly to the left of Simon Rattle’s podium and not more than two meters from the spot where Anna delivered a spellbinding performance of Felix Mendelssohn’s masterpiece. At the conclusion of the final movement, the twenty-five hundred members of the audience rose to their feet and showered her with rapturous applause and shouts of “Bravo!” Only then, with a mischievous smile, did she acknowledge Gabriel’s presence.

“Better?” she mouthed.