Alone in his office on Sunday night, Pierre Papin pursued the question of Carver, the girl, and the train they had taken out of Paris. A check on the ticket machines at the Gare de Lyon had come up with more than a dozen purchases made during the missing minutes when Carver could have used them. Four of these were for one ticket only. Papin was tempted to dismiss these, but he had to consider the possibility that the Englishman had dropped the girl and continued to a separate destination on his own.

Several of the ticket buyers had used credit cards, none in Carver’s name. But that was to be expected. If he had used a card, the name would certainly be that of an alias. So Papin was left with the task of checking twelve separate journeys, involving more than twenty individuals, hoping to track down his two suspects by a process of elimination.

It was a massive task and would require a great deal of cooperation. Ideally, Papin should ask for help from other departments, but he had no intention of doing that unless it was absolutely unavoidable. It was a matter of self-preservation.

It is said in politics that your opponents are in the other parties, but your enemies are in your own. Papin operated on the same principle. He had a visceral distrust of his colleagues in the various branches of the French security system. He knew they’d happily stab him in the back if it gave their department a moment’s advantage. That was the way the game worked in every intelligence community. It wasn’t the terrorists, the spies, and the other assorted dangers to national security you had to worry about. It was the bastard in the next office.

There had to be another way of tracking his prey. Papin put himself in Carver’s position: Okay, he arrives at the station with the girl. They split up in case anyone is looking for a couple. He tells her to go to the Milan train, makes a public show of buying tickets to Milan, and lets himself be seen on camera walking toward the appropriate platform. But unless he is engaged in a massive double bluff, he does not get on that train. He gets on another train, using tickets he has bought from a machine. Yet Carver and the girl do not return to the concourse….

Papin had been through the footage. Even if they had hidden their faces from the camera, he would have recognized them by their clothes or the way they walked.

So what does Carver do?

Papin got up from his seat and walked over to the small table where his cafetière was standing, poured out the last dregs into his dirty cup, and grimaced at the feel of the cold, gritty liquid on his tongue. He was about to spit it out into his wastebasket when the solution suddenly struck him. Of course! Papin’s face broke into a triumphant grin. Unless he had led his girl on a mad dash across the railway tracks, Carver must have got on whatever train was waiting on the platform opposite the one to Milan. Papin reached for a timetable and there it was, departing at thirteen minutes past seven, the express service to Lausanne, Switzerland. Carver and the girl had been on that train, he was absolutely certain of it.

As reluctant as he was to ask for help from any of his rivals in Paris, Papin had no hesitation in making a late-night call to Horst Zietler, of the Swiss Strategischer Nachrichtendienst, or Strategic Intelligence Service. Zietler had nothing to gain by screwing him. Papin got straight to the point.

“Horst, I need your help. I’m trying to find two people – a man and a woman. I think they arrived in Lausanne by train from Paris earlier today.”

“Anyone I need to be concerned about?”

“No, they’re no danger whatsoever to Switzerland. But…”

“They’re an embarrassment to France?”

Papin chuckled wearily. “Something like that. Let’s just say I’d like to know where they went once they arrived in your country.”

“So, what do you need?”

“Cooperation in Lausanne, interviews with any station staff who were on duty yesterday, maybe a look at security footage from, say, ten a.m. to noon. But, you understand, this is unofficial, off-the-record.”

“I’ll have a quiet word with the station manager in the morning. I’ll tell him you’re from the federal interior ministry, following up on a possible visa irregularity – purely routine, nothing to worry about. Your name will be Picard, Michel Picard. You’ll need an ID. I’ll e-mail a template: Work from that.”

“Thanks, I owe you.”

“Certainly, but I’m sure you can find a way of paying me back…”

Papin laughed again, this time with genuine amusement. “Well, now that you mention it, there’s a house we’ve been watching by the Parc Monceau, filled with remarkably beautiful girls. It’s attracted some very interesting clients with impressively exotic, imaginative sexual tastes. Perhaps I should send you some of the video footage to see if any Swiss citizens are involved. Purely as a matter of international cooperation, you understand.”

“Of course,” agreed Zietler. “What other reason could there be? As always, it’s a pleasure doing business with you, Pierre. The documentation you need is on its way.”

Papin was on the early-morning flight out of Charles de Gaulle to Geneva. He planned to be in Lausanne by the time the station manager arrived for work.

Carver woke just after three in the morning. It took him a second to work out where he was. He was lying on the sofa, still dressed, but someone had draped a duvet over him. He pondered the significance of the gesture. It certainly seemed like a good sign. Faced with a choice between killing him as he slept or making him comfortable and tucking him in, Alix had reached for the duvet.

So where was she? There was no one in the kitchen, nor in Carver’s office. The bathroom was empty, though a pair of women’s underpants was drying on the towel rack. That left only one possibility. Carver opened his bedroom door as quietly as possible and padded across the room.

She was in his bed. He could see the outline of her body under the sheet, the shock of her pitch-black hair against the white pillow. One arm was flung out in front of her, half-covering her face. As she breathed she let out an occasional soft, barely audible snuffle.

Carver smiled then shook his head as he recognized a long-forgotten emotion: affection.

Fancying a woman was one thing. But when you heard her snore and thought she was cute, well, then you knew it was serious.

It took an effort of will to turn around and leave the room. As he walked back down the hallway, Carver thought about everything Alix had said earlier. He believed the stuff about her joining the KGB. But the very fact that she had been trained to deceive men made him doubt the rest of her story.

She’s working behind the desk at a fancy hotel when some thug comes along and says, “Do a highly dangerous, top-secret mission with me in Paris, or I will tell the world you were a hooker?” No, that just didn’t sound credible. On the other hand, it didn’t automatically make her his enemy. There were all sorts of reasons why she might want to lie about her real identity and purpose. God knows he did it enough.

He checked his phones and office computer to see if she’d tried to talk to anyone or send any messages while he was asleep. His phones were routed through a sequence of relays that made it impossible for anyone to track where he was. The system also tracked any activity. There had been none at all. He logged on to his ISP mail server – nothing there either.

That left the stolen laptop. It was conceivable that Alix had used it. The bag was still on the kitchen chair where Carver had left it when they arrived at the flat. It looked untouched. But that meant nothing. She would have been smart enough to leave everything exactly as she’d found it.