"But they're not not totally unrelated." totally unrelated."

"How do you know this?"

"Jules, how good are you at math?"

"I am, in a word-two words-a cretin."

"Then I'm not going to try to explain asymmetric encryption to you. Let's just say that this number here is like that box I was talking about."

"The one with all the locks?"

"Yes. But this number is also the key key to the box." to the box."

"It is its own own key?" key?"

"In a way. All encrypted messages now are actually numbers. The original message-we call it a 'plaintext'-is encrypted using-"

"Please, recall I am a cretin-"

"Using what we call a 'one-way function.' A one-way function does something tricky to a series of numbers that can't be reversed. To put the lock on the box, we turn the plaintext message into a series of numbers, and then we do something tricky to these numbers that can only be undone if the receiver has the keys to it-"

"And now my head begins to throb."

"Have some more wine . . . Good . . . Yes, me too . . . Okay, how that is done is that everyone has access to the receiver's 'public key'-a number like this-made by multiplying two prime numbers. So anyone can send her a message using this public key number and an encryption program, but only the receiver can decipher the message because only the receiver knows the two primes she used to create her public key number-"

"Like the box?"

"Yes. For reasons too irritating to go into, we use prime numbers for this kind of encryption. On this chip, the number here is a public key made by multiplying two secret primes. To open it, we need to know-"

"What the two secret primes were. Okay, so we use a computer-"

"Yes, it's called 'factoring.' Want to know how long that would take factoring this number?"

"Yes, please."

"About eight hours. This isn't really an encryption attempt here. The number's too small. For a real encryption, the number might be in the trillions. It would take all the computers in the world five years to factor out the primes for a really large number. This isn't an attempt at encryption, it's a message message to me personally, and the message is that the person who sent this has an understanding of asymmetric encryption-" to me personally, and the message is that the person who sent this has an understanding of asymmetric encryption-"

"And that he knows you do too?"

"Yes."

Duhamel looked at the screen.

408 508 091.

"Do you know what the two secret primes are that make this number?"

"Yes: 18313 and 22307. Both are prime numbers. Multiply them together and you get 408508091."

"That's amazing! How did you do that?"

"Morgan is like you: he hates math. I once tried to teach him what I'm trying to teach you."

Duhamel was quick, Briony thought, but the speed of his reply was surprising: "And this is the number you used, yes?"

She looked at him without expression, and his chest began to tighten, seeing for the second time the steel under the velvet skin.

"Yes. That's . . . amazing. You missed your calling."

"I should have been a spy, you mean?"

"Maybe . . . Anyway, now what do we do? I know this has to do with Morgan. There's no other explanation. The number makes that clear. So, what do we do?"

"As I said, take it to your boss."

Silence, and her large gray eyes on his, unblinking.

"I can't. I can't take that chance. I need to know."

"To know, and then to decide?"

"Yes."

"Do you want me to go away?"

She softened, her shoulders slumping, her eyes glistening.

"No, I don't. I should, but I can't can't."

"I will leave, if you wish. But to know, you must open it."

She stared at the thing, her face full of dread. Duhamel reached out and touched her hand. She looked up, her eyes glistening.

"Then, for now, do nothing. Perhaps in the morning things will seem more clear. Why hunt grief?"

She sighed, and a shudder ran through her. Duhamel got up, took her hand, and led her upstairs. Duhamel knew what was in the memory chip, knew that after she opened it things would change between them.

But not just yet.

UH-60 BLACKHAWK CHOPPER.

155 MPH, ALTITUDE 6,000 FEET,.

304 MILES NNE SANTORINI.

INBOUND OVER TURKEY.

Mandy, in the copilot's seat-cold, tired, her entire body throbbing to the complex beat of the aging Blackhawk's rotors and the deafening howl of its turbines-was watching, without enjoyment, the strobing lights of the two Hughes OH-6 Cayuse choppers that had picked them up as they crossed the coastline of Turkey about an hour and a half ago. Also known as "Little Birds," they were small egg-shaped machines, each bearing the marking TURKISH AIR DEFENSE SERVICE, each with a machine gun visible in its open bay door.

They had one chopper on their port side and another on their starboard, which created in Mandy's mind the image of a pair of crows harassing a condor. These Little Birds had made radio contact with the Blackhawk when they were ten miles off the Aegean coast of Turkey, a young male voice asking, in accented English and with cool efficiency, who they were, why they were flying a chopper with the markings of the United Nations, what their intentions were, and, finally, why they had filed no flight plan. All excellent questions, thought Mandy at the time.

Dalton had told them they were UN medical officers inbound for Istanbul on an emergency mission to the Hastanesi Children's Hospital in Beyoglu, that they were carrying a donor heart for an urgent transplant case, and that they had filed a formal flight plan as soon as the heart had become available.

Reactions to this statement varied.

From the coolly efficient pilot of the Little Bird on their port side-Mandy's side-there had been a prolonged silence followed by an order to maintain level flight, to make no evasive maneuvers, and to await further instructions.

From Dobri Levka, sitting on one of the two gunners seats-in his case, the starboard-fondling the rusty pintle-mounted 7.62mm machine gun in the bay, there was shocked silence, and a kind of sinking dismay that his new employer had turned out to be a suicidal lunatic, followed shortly by a typically Balkan acceptance of the fact that fate seemed determined to see him either dead or in a Turkish prison before dawn. He patted the pockets of his medical corpsman's BDUs, found in one of the lockers and into which he had happily changed, being painfully aware that peeing in your pants had a chafing effect on the inner thighs, and extracted a bottle of ouzo from a case that had also been hidden in the locker. He downed a third of it in one go, which helped tremendously.

Mandy, for her part, simply stared at Dalton for a while, shook her head, and settled into the copilot's seat a little deeper, trying without much hope to find a way to be comfortable in it, which was not the maker's intent. Her silence was eloquent, as was the taut tense way in which she was resisting the meager military comforts of the pipe-and-canvas chair.

The interior of the Blackhawk's cockpit had been painted matte-black-"Helps with the night vision," Dalton had offered, to a cool reception-and the control panel was a migraine-inducing array of red, green, yellow, and amber lights coming from the altimeter dial, the compass and horizon indicators, the RPM indicator slides for both engines, and the large multifunction display panel in the middle. A pale green glow shone down on Mandy from the lights in the breaker systems arrayed overhead. Through the overhead window, she could see the blurring fan of the rotors and, beyond that, a starless, moonless sky.

A few minutes later, there was a burst of static, and Little Bird 1 came back on the air to inform them, in vaguely accusatory tones, that the night-desk nurses at Hastanesi Children's Hospital in Beyoglu had no record of any heart-donor flight scheduled to arrive from anywhere in Greece.

Dalton replied, with righteous indignation, that the recipient, a three-year-old girl named Asya Hamila-this brought a sidelong look from Mandy, who knew the man was slick, but where did that that name come from?-was being brought in by Red Crescent Air Ambulance from an outlying village in Turkey, the name of which he had not been told, that he knew for a fact that all proper arrangements had been duly cleared with Ankara, that this was, after all, a medical emergency, with a child's life hanging in the balance, and not the time for bureaucratic meddling, and did Little Bird 1 now wish him to throw the donor heart overboard, turn around, and go home, and let the United Nations, the Red Cross, Ankara, Reuters, the Associated Press, and Little Bird 1's immediate superiors sort out who was to blame for the needless death of an innocent girl? name come from?-was being brought in by Red Crescent Air Ambulance from an outlying village in Turkey, the name of which he had not been told, that he knew for a fact that all proper arrangements had been duly cleared with Ankara, that this was, after all, a medical emergency, with a child's life hanging in the balance, and not the time for bureaucratic meddling, and did Little Bird 1 now wish him to throw the donor heart overboard, turn around, and go home, and let the United Nations, the Red Cross, Ankara, Reuters, the Associated Press, and Little Bird 1's immediate superiors sort out who was to blame for the needless death of an innocent girl?

More radio silence followed.

Then, eventually, a rather stiff reply: a decision had been made to allow them to cross Turkish airspace under close escort, to avoid passing over any built-up areas, to stay at least fifty miles away from Ankara, and to land at Ataturk Field in Istanbul, where, if their story checked out, they would receive a police escort to Hastanesi Children's Hospital, and, if it did not, they would then be invited to enjoy the gracious hospitality of the Turkish Military Police.

This conversation had taken place approximately three hundred miles back, and little else had been said in the pilot cabin since then. It would be reasonable to describe the atmosphere in the copilot and pilot's section of the chopper during this period of onrushing travel as "frosty," while in the stripped-down cargo section the atmosphere, now rich in ouzo fumes and the scent of one of Levka's Turkish cigarettes, was much more festive.

Through the windshield, in the formless dark, under a starless sky, the lights of a town could now be seen; the lakeside city of Bandirma, according to the GPS array in the control panel. To the north, beyond the scattered grid of town lights, a vast darkness-the Sea of Marmara, and on the farther side of that, fifty miles over black water, the ancient and storied city of Byzantium, for now just a pale glow on the northwestern horizon, but racing toward them like a verdict. Mandy, watching the lights of Istanbul shimmer in the distance, set her cold coffee down in the holder and clicked on her headset mike, switching the com-net from CREW to PILOT ONLY mode.

"Micah, darling, may I raise a tiny issue with you, at the risk of seeming to whinge?"

"Please. You know how I adore your voice."

"Do you? Well, that's lovely. 'Absolutely peachy, peachy,' as Porter would say. My question is-and I ask this in the full expectation of a wonderfully comforting reply, knowing your remarkable skills, your ineffable tradecraft, your matchless derring-do-just precisely precisely how will our being buggered hourly in a Turkish prison speed our plow? Of course, as you have not had the advantages of an English public school education, being buggered hourly may be a new experience for you and one to which you may take a fancy. But it how will our being buggered hourly in a Turkish prison speed our plow? Of course, as you have not had the advantages of an English public school education, being buggered hourly may be a new experience for you and one to which you may take a fancy. But it does does seem rather a distraction from our main mission, does it not? Just asking, dear boy." seem rather a distraction from our main mission, does it not? Just asking, dear boy."

"You're starting to sound like the Queen Mum, you know?"

"I could do worse. At least she found great consolation in Tanqueray. I await your reply."

"Speed."

"Speed?"

"Speed is what this is all about, Mandy. We have to get inside the decision cycle of whoever is running this operation. Keraklis called Istanbul and mentioned the is what this is all about, Mandy. We have to get inside the decision cycle of whoever is running this operation. Keraklis called Istanbul and mentioned the Subito Subito. He called"-Dalton checked his watch-"at 1854 hours, a little before seven in the evening. It's now almost two in the morning. Sofouli won't find Keraklis and the missing chopper until he gets up. Whoever was running Keraklis will be wondering why he hasn't heard back. But it's a good bet that he won't get really concerned about it until the morning. By then, we'll be right in his face, exactly where he won't be expecting-"

"Whoever he he is-" is-"

"Yes. In short, we'll be inside his decision cycle-"

That put Mandy over the top.

"Oh bugger bugger his decision cycle. Couldn't we have taken a civilian flight? Or do you just like commandeering things?" his decision cycle. Couldn't we have taken a civilian flight? Or do you just like commandeering things?"

"Even inside the EU, they ask for papers at the airports. Which travel documents would you have used? The Pearson passports, which, by the time we got to Athens, would have set off alarms all over the airport? Our personal papers, which would kick off triggers back in Langley. Or would we just tell them we were CIA agents on a goodwill tour to Turkey? You know how well we're getting along with Turkey these days. You heard Keraklis talking to someone at Atakoy Marina about the Subito Subito. That boat's a crime scene, supposedly the scene of Kiki Lujac's murder, and I want to go over it before they put it somewhere we'll never find it-"

"We don't know the Subito Subito is at this marina-" is at this marina-"

"And we don't know it isn't, but if we stay inside the decision cycle-"

"If you use that phrase again, Micah, I swear I will strike you. We will also be inside inside a Turkish prison, as I have pointed out-" a Turkish prison, as I have pointed out-"

"No, we won't."

"No? Now I'm all aflutter. Why not, pray tell?"

"We're going to lose our escort."

Mandy gave him one of her raised-eyebrow looks, but since it was quite dim in the cabin and he couldn't see her face, he was able to survive it.

"Oh goody," she said. "I just knew knew you'd have a plan. How you'd have a plan. How are are you going to lose our little friends? Really?" you going to lose our little friends? Really?"

"Do you want to know? Really?"

"No, not really. Well, yes . . . yes, I do."

Dalton told her straight out, and since then she had been, for her, unnaturally silent. Now, with the lights of Bandirma under their feet and the black void of the Sea of Marmara eating up the rest of the forward universe, the time for acting was growing very short.

Dalton got on the CREW com-net to Levka.

"Levka, how are you doing back there?"

His voice came back, a little oversprightly but coherent.

"I am good, boss. I have machine gun working, if you like?"

"How'd you do that?"

"Found oil can in locker. Also big box of 7.62. You want I shoot up a Turk soldier for you? I never liked Turk soldiers."

"Not right now. What else is back there?"