The screaming of the steel wheels eased as the train crawled the last dozen metres toward the Kehl Bridge checkpoint, then faded to a grinding hum as the brakes settled them to a halt. The carriage rocked once, twice, then stilled.

For a few seconds, there was only the ticking of metal cooling and the distant hiss of steam. Then the thud of boots began at the forward end of the Abteilwagen, heavy soles marching in rhythm along the corridor.

Bleichert inhaled sharply and glanced at the door. "Sie sind hier ... They are here."

David slid the Passierschein from his outer pocket and laid it on his knee, the red seal facing outward. "Let them see what they want to see."

The boots drew nearer. Voices barked in the next compartment, muffled by wood and frosted glass. A door slammed. Another opened. More voices. Then the handle of their own door rattled and slid back.

A Feldgendarmerie sergeant filled the doorway, boots planted wide, leather strap of his gorget gleaming across his chest. Behind him loomed two younger soldiers with carbines slung and bayonets fixed.

"Grenzkontrolle! Papiere!" the sergeant barked.

David looked up at him with what he hoped was the right mix of professional calm and mild impatience. "Aber natürlich, Feldwebel." He picked up the Passierschein with two fingers and extended it, the seal foremost.

The sergeant took it, squinted at the wax, then at the heading. His lips moved as he read, "Im Namen Seiner Kaiserlichen Hoheit des Kronprinzen Wilhelm ..." He glanced back at David's face, at his suit, and at the small leather sample case on the bench beside him. "You are travelling on behalf of the Crown Prince?"

David nodded. "Im Dienste des Kronprinzen, ja ... watches and wine for his staff at the Front."

The man's gaze dropped to the floor. The dark edge of the wooden box Bleichert had nudged beneath David's bench lay just inside the fringe of the velvet skirting. A boot shifted behind him.

"Und er?" The sergeant jerked his chin at Bleichert.

"A wine producer from Elsass," David answered, before Bleichert could speak. "He is bringing samples for the governor in Straßburg, who approves our deliveries. The railway lines south of Sélestat are closed, requiring a long and tedious detour through Freiburg and Offenburg to here."

The sergeant's eyes narrowed. "A detour via Baden?"

David allowed himself a small, weary shrug. "The war forces us all down strange paths, Sergeant. But his mission is serious, and it depends on my escort." He pointed at the pass. "It says there that delays to my service are to be avoided, and ensuring his success is part of that service."

The sergeant looked back down at the document, then turned it over to examine the reverse. He jabbed a thick finger at the signature and the seal. "Who issued this?"

"The Crown Prince's military staff. When this is accomplished, they are expecting me in Metz this afternoon." He glanced at his watch and blew a loud, exasperated breath. "At five o'clock. If I am late because of your interference, nobody will be happy, particularly not you."

One of the younger guards shifted his weight. "Herr Feldwebel, wir sollen heute ... we must still search all the third-class cars."

"Yes, we do," the sergeant snapped and handed the pass back, more carefully than he had taken it. "Your mission is important, sir ...?"

"Meier. Jakob David Meier. As it is written here."

"I will instruct my men to pass quickly through the rear carriages, mein Herr." He glanced at the hidden edge of the wooden box. "What you carry for the war is none of my business, as long as the war is not fought only with bottles."

With the hint of a smile, he stepped back into the corridor and said, "Onward! Quickly! The next carriages. Time to harass only a few farm wives." The door closed with a quiet click, and the sound of boots moved on.

For several heartbeats, neither man spoke. Then Bleichert let out a long, slow breath. "Mein Herr ... if I live another fifty years, I will not forget what you have done."

David tucked the Passierschein back into his pocket. "Pray that no one else remembers it too clearly." He looked at the wooden box under his bench. "When we reach Straßburg, you will take that directly to the governor. Do not pause along the way."

"Oui, ja. I will go straight from the platform to his office." Bleichert wiped his palms again on his trousers. "And then, perhaps, our wines will see bottles again ..." He paused as the train jerked once as the locomotive took up the slack.

Through the frosted glass, the concrete, wire and iron of the checkpoint began to slide past, replaced again by open air and the glinting water of the Rhein below. Then Bleichert added, "If ever you need Zahnacker, you have more than earned it."

David nodded, then leaned his head against the linen-covered rest and closed his eyes. The Passierschein had worked more smoothly than he had dared hope. Stronger than I imagined. But dangerous to test too often.

He opened his eyes and glanced at his watch – 12:32. If the line remained clear and the shuttle kept to its schedule, he would be in Straßburg well before thirteen hundred. With more than four hours in hand, ample time. Check the Metz departure board. See if there's enough time to give Bleichert safe passage out of the station. Hans's voice echoed in his mind – Shape first, details later.

Ahead lay a city crowded with guards and suspicions, and beyond that was a railway to Metz and a prince waiting on a command train. The next obstacles wouldn't be concrete, barbed wire and officiousness; they would be gaudy uniforms, privilege, etiquette and vanity.

He settled back into the plush seat, felt the Abteilwagen gather speed and let the rhythm of the rails carry his thoughts forward toward the next encounter.