“As you can see, there are a series of symbols-graphemes, if you want to be technical-engraved around the inside.”

“What is a grapheme?” Marks asked.

“The basic unit of language, any language, really.”

Willard squinted. “Yes, but what the devil language is it?”

“Its own, manufactured out of ancient Sumerian, Latin, and God alone knows what other dead language, possibly one that’s been lost to the modern world.”

“You want us to drop everything for this?” Marks looked incredulous. “Who do you think we are, Indiana Jones?”

Liss, who had been in the process of chewing a bite of food, smirked. “This is not so old as that, my smart-aleck friend. In fact, it probably hasn’t been in existence more than a decade or two.”

“A ring?” Willard shook his head. “What do you want with it?”

“Eyes Only.” Liss winked and tapped the side of his nose. “In any event, Noah had the ring when he was killed by Jason Bourne. It’s clear that Bourne killed him in order to get the ring.”

Marks shook his head. His lack of antipathy toward Bourne was well known. “Why would he do that? He must have had a good reason.”

“What you need to keep in mind is that Bourne has murdered again, without provocation.” Liss looked hard at him. “Find Bourne and you’ll find the ring.” He carefully broke a yolk and dipped a triangle of toast into it. “I got a tip that Bourne was seen in the Heathrow arrivals terminal, so it’s a good bet he’s gone to Noah’s apartment in Belgravia. Start there. I’ve sent all the particulars to your cells and booked you on an evening flight to Heathrow so you’ll be bright-eyed, bushy-tailed, and ready to hit the tarmac at a full sprint when you arrive tomorrow morning.”

Willard put aside the photos and made a face that sent warning bells ringing in Marks’s head.

“When you agreed to fund Treadstone,” Willard said in a quietly ominous voice, “you agreed that I would be in charge of operations.”

“Did I?” Liss rolled his eyes as if trying to recall. Then he shook his head. “No. No, I didn’t.”

“Is this… What is this, some kind of joke?”

“I don’t think so, no.” Liss popped the toast triangle into his mouth and chewed luxuriously.

“I have a very specific agenda.” Willard carefully enunciated each word with a cutting edge. “A particular reason for jump-starting Treadstone.”

“I’m well aware of your obsession with this Russian Leonid Arkadin, but the fact is, Frederick, you didn’t jump-start Treadstone. I did. Treadstone is mine, I fund it lock, stock, and ammunition. You work for me, to think otherwise is to gravely misjudge the parameters of your singular employment.”

Marks suspected that it had dawned on Willard that by switching from CI to Oliver Liss, he’d merely exchanged one hated taskmaster for another. And as he himself had said when he’d recruited Marks, there was no turning back from a deal with the devil. They were both in this to the bitter end, into whatever circle of hell that might lead them.

Liss was also watching Willard. He smiled benignly and pointed with the eggy tines of his fork. “You’d better eat up, your breakfast is getting cold.”

After catching a bite to eat, during which time he read more of Perlis’s account of the blood feud between Arkadin and Oserov, Bourne returned to Belgravia, this time to the street where Tracy Atherton had lived. It was green and cool through the mist that swirled in the gutters and entwined around the chimneys of the row houses. Her house was neat and trim, identical to its neighbors. A steep flight of steps ran up to the front door where, he observed, there was a brass plate with the names of the people inhabiting the six flats.

He pressed the bell for T. ATHERTON, as if she were still alive and he was arriving to spend the afternoon with her in cozy repose, drinking, eating, making love, and talking about art and its long, complex history. He was surprised, then, when the buzzer sounded, unlatching the front door. Pushing his way inside, he found himself in a narrow vestibule, dim and damply chilly in the way only London indoor spaces can be in winter or spring.

Tracy’s flat was on the third floor, up flights of narrow, very steep stairs, the treads of which creaked beneath his weight now and again. He found it all the way in the rear and he recalled her saying, “There’s a mews out back with a flowering pear tree that a pair of house martins nest in come spring.” He imagined the house martins would be nesting there right about now. It was a bittersweet thought.

The door opened a crack as he was warily approaching. The figure that revealed itself was backlit and for a moment he stood stock-still, his heart racing, because he was quite certain he was looking at Tracy. Tall, willowy, blond hair.

“Yes? May I help you?”

Her eyes broke the spell; they were brown, not blue, and they weren’t as large as Tracy’s. He felt himself breathe again. “My name is Adam Stone. I was a friend of Tracy’s.”

“Oh, yes, Trace told me about you.” She did not offer her hand. Her expression was carefully neutral. “I’m Chrissie Lincoln, Tracy’s sister.”

Still, she did not move out of the doorway. “She met you on a flight to Madrid.”

“Actually, the flight was from Madrid to Seville.”

“That’s right.” Chrissie watched him warily. “Trace traveled so much, it was a good thing she liked flying.”

Bourne could see that he was being tested. “She hated flying. She got sick on the flight five minutes after she introduced herself.” He waited for her to say something, then: “May I come in? I’d like to speak to you about Tracy.”

“I suppose.” She stood back, almost reluctantly.

He walked in and she closed the door behind him. Tracy had been right, the flat was tiny, but as beautiful as she had been. Furniture in butter yellows and deep oranges, crisp cream curtains framed each window, throw pillows here and there in polka dots, animal prints, and stripes added bright bits of color. He walked across the living room and into her bedroom.

“Are you looking for something in particular, Mr. Stone?”

“Call me Adam.” Somehow he knew there would be French doors out onto the back, and there was the pear tree in the mews. “I’m looking for the house martins.”

“I beg your pardon?” Her voice was pitched a bit higher, thinner, and her speech was more rapid than her sister’s had been.

“Tracy said that come spring a pair of house martins nested in that pear tree.”

She was at his shoulder. Her hair smelled of lemon. She wore an inexpensive cotton man’s shirt with the sleeves rolled up, revealing sun-browned arms, jeans, not the fashionable low-riding ones, but sturdy Levi’s with the cuffs rolled up, cheap flats, scuffed and worn at the heels, and was in a light sweat as if she had been cleaning or rooting around for some time. She wore no jewelry, not even a wedding band. And yet her last name was Lincoln, not Atherton.

“Do you see a sign of them?” she asked in a brittle voice.

“No,” he said, turning away.

She frowned momentarily and remained silent for a long time.

“Chrissie?”

When she didn’t answer he went and got her a glass of cold water from the kitchen. She took it without comment and drank it slowly and methodically, as if it were medicine.

When she put the glass down, she said to him, “I’m afraid this was a mistake letting you in. I’d prefer if you left.”

Bourne nodded. He’d seen the flat; he didn’t know what he’d expected to find, maybe it was nothing at all, save the scent of her, lingering long after she had left. The night they had shared in Khartoum was far more intimate than if they had made love, an act that despite its name could seem impersonal, even detached. The revelation that came later, that Tracy had been working for Leonid Arkadin, had come like a cold slap across the face. But in the weeks after her death he’d been haunted by the notion that something was wrong with that equation. Not that he doubted she’d been in Arkadin’s employ, but deep down he couldn’t escape the notion that the story wasn’t that simple. It was altogether possible that he’d come here looking for some form of proof, a confirmation of his suspicion.