THE QUEST FOR GABRIEL WAS NEARLY AS INTENSE as the search for the perpetrators of the massacre in Rome. He was a man who never telegraphed his movements and was no longer under Office discipline, so it surprised no one, least of all Shamron, that he’d left Venice without bothering to tell anyone where he was going. As it turned out, he’d gone to England to see his wife, Leah, who was living in a private psychiatric hospital in a secluded corner of Surrey. His first stop, however, was New Bond Street, where, at the behest of a London art dealer named Julian Isherwood, he’d agreed to attend an Old Master sale at Bonhams auction house.

Isherwood arrived first, clutching a battered attaché case in one hand and the throat of his Burberry raincoat with the other. A few other dealers were huddled in the lobby. Isherwood murmured an insincere greeting and loped off to the cloakroom. A moment later, relieved of his sodden Burberry, he took up watch near the window. Tall and precarious, he was clad in his customary auction attire, a gray chalk-stripe suit and his lucky crimson necktie. He arranged his windblown gray locks to cover his bald spot and briefly examined his own face reflected in the glass. Hungover, a stranger might have assumed, perhaps a bit drunk. Isherwood was neither. He was stone-cold sober. Sharp as his mother’s tongue. He flung out his arm, pushed his French cuff from his wrist, and shot a glance at his watch. Late. Not like Gabriel. Punctual as the Nine O’clock News. Never one to keep a client cooling his heels. Never one to fall behind on a restoration-unless, of course, it was due to circumstances beyond his control.

Isherwood straightened his necktie and lowered his narrow shoulders, so that the figure peering back at him had the easy grace and confidence that seemed the birthright of Englishmen of a certain class. He moved in their circles, disposed of their collections, and acquired new ones on their behalf, yet he would never truly be one of them. And how could he? His backbone-of-England surname and lanky English bearing concealed the fact that he was not, at least technically, English at all. English by nationality and passport, yes, but German by birth, French by upbringing, and Jewish by religion. Only a handful of trusted friends knew that Isherwood had staggered into London as a child refugee in 1942 after being carried across the snowbound Pyrenees by a pair of Basque shepherds. Or that his father, the renowned Berlin art dealer Samuel Isakowitz, had ended his days on the edge of a Polish forest, in a place called Sobibor.

There was something else Julian Isherwood kept secret from his competitors in the London art world-and from nearly everyone else, for that matter. Over the years he had done the occasional favor for a certain gentleman from Tel Aviv named Shamron. Isherwood, in the Hebrew-based jargon of Shamron’s irregular outfit, was a sayan, an unpaid volunteer helper, though most of his encounters with Shamron had been closer to blackmail than voluntarism.

Just then Isherwood spotted a flash of leather and denim amid the fluttering mackintoshes of New Bond Street. The figure vanished for a moment, then reappeared suddenly, as though he had stepped through a curtain onto a lighted stage. Isherwood, as always, was taken aback by his unimpressive physical stature-five-eight, perhaps, a hundred and fifty pounds fully clothed. His hands were thrust into the pockets of a car-length black-leather jacket, his shoulders were slumped slightly forward. His walk was smooth and seemingly without effort, and there was a slight outward bend to his legs that Isherwood always associated with men who could run very fast or were good at football. He wore a pair of neat suede brogues with rubber soles and, despite the steady rain, carried no umbrella. The face came into focus-long, high at the forehead, narrow at the chin. The nose looked as though it had been carved from wood, the cheekbones were wide and prominent, and there was a hint of the Russian steppes in the green, restless eyes. The black hair was cropped short and very gray at the temples. It was a face of many possible national origins, and Gabriel had the linguistic gifts to put it to good use. Isherwood never quite knew who to expect when Gabriel walked through the door. He was no one, he lived nowhere. He was the eternal wandering Jew.

Suddenly he was standing at Isherwood’s side. He offered no greeting, and his hands remained jammed in his coat pockets. The manners Gabriel had acquired working for Shamron in the secret world had left him ill-equipped to function in the overt one. Only when he was playing a role did he appear animated. In those rare flashes when an outsider glimpsed the real Gabriel-such as now, thought Isherwood-the man they saw was silent and sullen and clinically shy. Gabriel made people supremely uncomfortable. It was one of his many gifts.

They walked across the lobby toward the registrar’s desk. “Who are we today?” Isherwood asked sotto voce, but Gabriel just leaned over and scrawled something illegible in the logbook. Isherwood had forgotten that he was left-handed. Signed his name with his left hand, held a paintbrush with his right, handled his knife and fork with either. And his Beretta? Thankfully, Isherwood did not know the answer to that.

They climbed the stairs, Gabriel at Isherwood’s shoulder, quiet as a bodyguard. His leather coat did not rustle, his jeans did not whistle, his brogues seemed to float over the carpet. Isherwood had to brush against Gabriel’s shoulder to remind himself he was still there. At the top of the stairs a security guard asked Gabriel to open his leather shoulder bag. He unzipped the flap and showed him the contents: a Binomag visor, an ultraviolet lamp, an infrascope, and a powerful halogen flashlight. The guard, satisfied, waved them forward.

They entered the salesroom. Hanging from the walls and mounted on baize-covered pedestals were a hundred paintings, each bathed in carefully focused light. Scattered amid the works were roving bands of dealers-jackals, thought Isherwood, picking over the bones for a tasty morsel. Some had their faces pressed to the paintings, others preferred the long view. Opinions were being formed. Money was on the table. Calculators were producing estimates of potential profit. It was the unseemly side of the art world, the side Isherwood loved. Gabriel seemed oblivious. He moved like a man accustomed to the chaos of the souk. Isherwood did not have to remind Gabriel to keep a low profile. It came naturally to him.

Jeremy Crabbe, the tweedy director of Bonhams’ Old Master department, was waiting near a French school landscape, an unlit pipe wedged between his yellowed incisors. He shook Isherwood’s hand joylessly and looked at the younger man in leather at his side. “Mario Delvecchio,” Gabriel said, and as always, Isherwood was astonished by the pitch-perfect Venetian accent.

“Ahhh,” breathed Crabbe. “The mysterious Signore Delvecchio. Know you by reputation, of course, but we’ve never actually met.” Crabbe shot Isherwood a conspiratorial glance. “Something up your sleeve, Julian? Something you’re not telling me?”

“He cleans for me, Jeremy. It pays to have him look before I leap.”

“This way,” Crabbe said skeptically, and led them into a small, windowless chamber just off the main saleroom floor. The exigencies of the operation had required Isherwood to express a modicum of interest in other works-otherwise Crabbe might be tempted to let it slip to one of the others that Isherwood had his eye on a particular piece. Most of the pieces were mediocre-a lackluster Madonna and child by Andrea del Sarto, a still life by Carlo Magini, a Forge of Vulcan by Paolo Pagani-but in the far corner, propped against the wall, was a large canvas without a frame. Isherwood noticed that Gabriel’s well-trained eye was immediately drawn to it. He also noticed that Gabriel, the consummate professional, immediately looked the other way.