Wilhelm lifted his glass again for a final sip of the Yquem, then set it down and rang a small silver bell on the table beside him. A moment later, the door at the far end of the railcar opened, and an adjutant stepped in, heels clicking together.

"Ja, mein Prinz?"

"Rufen Sie den Bahnhofskommandanten," Wilhelm said, waving a hand in a small circle. "Call the station commander."

The adjutant bowed and disappeared. Within a minute, he returned with a tall officer in a dark-green tunic who stopped just inside the salon and saluted. "Your Imperial Highness?"

Wilhelm gestured lazily with two fingers. "Herr Kommandant, this gentleman –" he nodded toward David – "will require a suite for the night at the Palais du Gouverneur. A quiet set of rooms, with hot water that does not take an hour to arrive."

The commander inclined his head. "At once, sir."

"And," Wilhelm added, "inform the kitchens that I am bored with army fare. I expect dinner for two this evening, prepared to Parisian standards, not Saarbrücken canteen standards. Fish, meat, proper sauces. Tell them I will bring the wines, white, red, and dessert, all of the highest French quality."

"Jawohl, Herr Kronprinz." The man's gaze lingered on the open bottles, then back to Wilhelm's face. "Shall they expect you at your usual 19:00?"

"Yes," Wilhelm confirmed. "And see that the staff understand – this is to be an evening without interruptions. No telephone calls, no messengers, no unnecessary telegrams. If the world ends, they may inform me with morning coffee."

"As you wish." Another salute, and the adjutant withdrew, closing the door softly behind him.

Wilhelm leaned back and exhaled through his nose. "If I must be chained to Metz, David, I shall at least eat as if I were in Paris."

"A civilised form of defiance, sir."

"The only one left to me most days," Wilhelm replied as he watched David cram the cork ends into the bottle necks. "These will serve well to remind the Palais du Gouverneur what wine was like before this war."

He stood and straightened his tunic. "Come. We will escape before any more obligations intrude to disturb our anticipation."

A few minutes later, as they approached a gatehouse, two sentries in field-grey uniforms stepped out from their guard boxes. Then, recognising the Imperial standard fluttering from the car's front fender, they snapped to a rigid, motionless salute.

The Mercedes rolled into the enclosed courtyard, the low rumble of its engine echoing off the high limestone walls. Before the car had stopped, two liveried footmen stepped forward, ready to open the doors.

Inside, a minute later, David felt the atmosphere as a tense mix of a military operational headquarters and a royal court. An aide shifted from foot to foot, holding a leather dispatch bag while liveried footmen stood in silent attendance.

Wilhelm offered David a brief nod. "It appears I must receive a dispatch from the fortress commander. My orderlies will see you to your quarters. You will be brought to our salon at seven."

A young Prussian lieutenant, stiff-backed and impeccably polite, stepped forward to escort David. They walked through a labyrinth of carpeted galleries, their walls adorned with massive oil paintings of Hohenzollern ancestors and elaborate tapestries celebrating Prussian military triumphs. Then through a door at the end, the distant hum of typewriters and ringing military telephones fell silent.

The lieutenant unlocked a pair of double doors, opened one and stepped aside with a sharp click of his heels. "Your suite, sir. The Crown Prince has ordered that you are not to be disturbed. Should you require anything, please use the service bell button."

After his suitbag and case were laid on the bench, the doors closed, and David stood alone in a spacious, high-ceilinged apartment. His attention was drawn to a freshly-lit fire crackling in the carved green marble fireplace, and he realised just how far he had wandered into Germany.

He settled onto the plush chaise longue facing the fire, leaned back and took stock. Relaxing in a luxurious bubble of absolute privilege, completely insulated from the brutal war raging just beyond the horizon. It feels safe. But am I? Wilhelm showed no sign of suspicion. At least none I noticed. What have I learnt? What more can I learn without appearing to press?

After a long reflection, he rose and explored the rest of the suite. Through a set of recessed pocket doors, he examined the massive, four-poster bed draped in heavy brocade curtains. In an adjacent alcove was a porcelain washbasin and a deep copper bathing tub, a steaming copper pitcher of hot water sitting on the bench beside it. Should I bathe? No need, I showered this morning, and I've not broken a sweat. Besides, this is too awkward.

He moved his bag into the bedroom, much lighter now without the fifty pounds of wine. After removing his suitcoat and shirt, he washed, pulled on a fresh shirt and fastened a new collar, then he stopped. Damn! Something Maria and I missed. No evening attire. The dark suit might pass, but my cravat is utterly inappropriate.

He looked around the room. Perhaps a piece of the dressing gown's sash. The deep blue is close to black. But how? It is too wide, even folded double. But better than the cravat.

He calculated the length needed, and before cutting, put it around his neck and examined the reflection. Then with it cut, folded double along its middle portion, he returned it to the collar around his neck and tied a bow. After adjusting it in the mirror to disguise much of the width and bulk, he stepped back to examine it at a greater distance. Passable at a yard – effectively at two with the reflection. But increasingly obvious closer.

Perhaps the service bell. See if the staff can find a tie. Surely others arrive unprepared. He glanced at his watch. But with less than eight minutes, this will have to do.

He had barely sat again by the fire when a knock sounded on the door, and he rose and opened it to the same young lieutenant who had escorted him here.

"Herr Meier, we shall go now, so that we do not keep His Royal Highness waiting. He is extraordinarily prompt."