“Memorize the CIA’s files on Ivan and his network, and read everything you can about Mary Cassatt. Adrian will tell you the rest.”

“ Kharkov and Cassatt? Only a Gabriel Allon operation could feature a combination like that.” She lowered her sunglasses. “Should I assume you’ll need me to go undercover again?”

“Yes, you should.” A silence fell between them, heavy as the midday heat. “If you don’t want to do it, Sarah, just tell me. God knows, you’ve done more than enough already.”

She looked at him and smiled. It was a brave smile, thought Gabriel. The kind that didn’t quite extend to the rest of the face. “And miss all the fun?” She fanned herself dramatically with her book. “Besides, I’d do just about anything to get out of here for a few days. I can’t stand Washington in the summer.”

27 LONDON

Number 7 Mornington Terrace was a sooty postwar apartment block overlooking the rail tracks of Euston Station. When Gabriel rang the bell of Apartment 5C, the door opened a few inches and a pair of gray eyes regarded him coolly over the chain. They didn’t look pleased to see him. They rarely did.

Free of the chain, the door swung open a more hospitable distance. Gabriel stepped inside and took stock of his surroundings: a dreary little bed-sit, with a cracked linoleum floor and flea market furnishings. The man waiting inside looked as though he had wandered into the flat by mistake. He wore a pin-striped suit, a Burberry raincoat, and cuff links the size of shillings. His hair had been blond once; now it had the cast of pewter. It gave him the appearance of a model in a magazine advertisement for fine cognac, or an actor in a soap opera, the older millionaire type who puts himself about with younger women.

Graham Seymour didn’t have time to pursue women. As deputy director of MI5, the British Security Service, he had more than enough work on his desk to keep him occupied. His country was now home to several thousand Islamic extremists with known terrorist connections. And just to keep things interesting, Russian espionage activities in London were now at levels not seen since the end of the Cold War. Those activities included the 2006 murder of Aleksandr Litvinenko, a former FSB agent and Kremlin critic who had been poisoned with a dose of highly radioactive polonium-210, an act of nuclear terrorism carried out by the FSB in the heart of the British capital.

Seymour must have arrived just before Gabriel because the shoulders of his coat were still beaded with raindrops. He tossed it wearily over the back of a chair and held out his hand. The palm was facing up.

“Let’s not do this again, Graham.”

“Hand it over.”

Gabriel exhaled heavily and surrendered his passport. Seymour opened the cover and frowned.

“Martin Stonehill. Place of birth: Hamburg, Germany.”

“I’m a naturalized American citizen.”

“So that explains the accent.” Seymour handed the passport back to Gabriel. “Is this a gift from your friend the president or the handiwork of your little band of forgers at King Saul Boulevard?”

“ Adrian was kind enough to let me borrow it. Traveling is hard enough these days without doing it on an Israeli passport bearing the name Gabriel Allon.” He slipped the passport back into his coat pocket and looked around the room. “Do you use this for all your high-level liaison meetings, Graham, or is this palace reserved for Israeli visitors?”

“Don’t get your nose bent out of shape, Gabriel. I’m afraid it was all we could find on short notice. Besides, you were the one who refused to come to Thames House.”

Thames House was MI5’s riverfront headquarters near Lambeth Bridge.

“I really like what you’ve done with the place, Graham.”

“It’s been in the family for years. We use it mainly as a crash pad and for debriefing sources and penetration agents.”

“What sort of penetration agents?”

“The sort that we slip into potential terrorist cells.”

“In that case, I’m surprised you were able to squeeze me in.”

“I’m afraid it does get its fair share of use.”

“Any of your sources picking up any whispers about Russian arms headed this way?”

“I put that question to the Joint Terrorism Analysis Centre last night after talking to Adrian. The Americans aren’t the only ones who’ve been hearing chatter about the arrows of Allah. We’ve intercepted references to them as well.”

In the galley kitchen, an electric teakettle began to spew steam. Gabriel walked over to the window and peered out at a passing West Coast Main Line train while Seymour saw to the tea. He returned with two cups, plain for Gabriel, milk and sugar for himself. “I’m afraid the housekeepers neglected to stock the pantry with digestive biscuits,” he said morosely. “It’s bad enough they left shelf milk instead of fresh, but failure to leave a package of McVitie’s is a firing offense, in my humble opinion.”

“I can run down to the corner market if you’d like, Graham.”

“I’ll survive.” Seymour lowered himself hesitantly onto the couch and placed his mug on a scratched coffee table. “ Adrian gave me the basics of what you picked up in Moscow. Why don’t you fill me in on the rest?”

Gabriel told Seymour everything, beginning with the murder of Boris Ostrovsky in Rome and ending with his interrogation and deportation from Russia. Seymour, who did nothing more dangerous these days than change his own ink cartridges, was suitably impressed.

“My, my, but you do manage to get around. And to think you accomplishedall that with only three dead bodies. That’s something of an accomplishment for you.” Seymour blew thoughtfully into his tea. “So what are you proposing? You want to pull Elena Kharkov aside for a private chat about her husband’s operations? Easier said than done, I’m afraid. Elena doesn’t put a toe outside her Knightsbridge mansion without a full complement of very nasty bodyguards. No one talks to Elena without talking to Ivan first.”

“Actually, that’s not exactly true. There’s someone in London she talks to on a regular basis-someone who might be willing to help, considering the gravity of the situation.”

“He’s a British citizen, I take it?”

“Quite.”

“Is he honestly employed?”

“I suppose that depends on your point of view. He’s an art dealer.”

“Where does he work?”

Gabriel told him.

“Oh, dear. This could be a bit ticklish.”

“That’s why I’m here, Graham. I wouldn’t dream of operating in London without consulting you first.”

“Spare me.”

“I think we should have a little look under his fingernails before we make any approach. The art world is filled with a lot of shady characters. One can never be too careful.”

“We? No, Gabriel, we won’t go anywhere near him. The Security Service will handle this matter with the utmost discretion and a proper Home Office warrant.”

“How soon can you start?”

“Seventy-two hours should suffice.”

“I’ll have a man on him by lunch,” Seymour said.“ I propose we meet once a day to review the watch reports.”

“Agreed.”

“We can do it here if you like.”

“Surely you jest.”

“Your choice, then.”

“St. James’s Park. Six o’clock. The benches on the north side of Duck Island.”

Graham Seymour frowned. “I’ll bring the bread crumbs.”