David went to his satchel and took out his hiking maps of the Schwarzwald, selected five and unfolded them on the floor. He traced his swagger stick along the routes of the Höllentalbahn and the Schwarzwaldbahn. "Many opportunities here. In one twenty kilometre stretch of the Black Forest line, there are forty tunnels, plus many bridges and viaducts."

"These are fine maps," Tompkins said as he knelt to examine the detail. "Different from our Ordinance maps."

"These are hiking maps, published by the Schwarzwaldverein, the Black Forest hiking association. They're fifty thousand to one, and I quilted together nine of them to cover the area when I was planning my escape over the mountains. I needed only three of them on the trip, but brought them all in case I needed to change plans along the way."

"Wise planning, that."

"I also have this," He held up a small book. "A pocket atlas of the German Empire. I bought it in a bookstore in Ghent as I began my evasion plans. It's a bit dated, the 1908 edition."

"Ghent? That's in Belgium, isn't it?"

"Yes. I was still in the German uniform then, but I seemed to fit in well among all the other walking wounded heading away from the front on sick leave. Their hospitals are overburdened, so they're sent home to recover."

He put the atlas down and turned to the maps, moving his stick across them. "This is the watershed between the Black Sea and the North Sea, between the Danube and the Rhine drainages. This line, the Sauschwänzlebahn, called the Pigtail Line because of its spiral and twists, is a vital link between the interior of Germany and the lower Rhine Basin. It gives the Germans a direct supply route to the trenches along the French border."

David drew three lines across the maps with his swagger stick. "They have three routes to supply the southern, central and northern portions of their front with France. Two through the Black Forest and one around its southern edge." Using the maps, he traced the route he had taken escaping over the mountains and showed the hidden camp sites they had used. "From the geological formations I saw along our route, I'd be surprised if there weren't many more as good or better throughout the entire area."

He tapped stick on the town of Erzingen and said, "My great aunt has a house here a hundred metres from the German-Swiss border." He tapped a few inches away. "Across the line into Switzerland, she has a large wine estate, with pastures and vineyards running from it across into Germany."

With another tap. "The vineyards cross the border here, and she has tool sheds on each side. They're small, crude stone structures about forty yards apart and half a kilometre, about five hundred yards from the Customs posts. The guards do random patrols along the border, and I suspect they have trip wires rigged to lights and alarms, as we had seen here." He pointed to the Wutach River near Erzingen. "We saw snipers kill a man when his movement switched on lights as he tried to cross into Switzerland here."

He looked at Tompkins, then concluded, "That's the layout. My thoughts involve a tunnel linking the two tool sheds. Would it be possible to get a team of Sappers?"

"Yes, certainly. We'd already been told of the need. We're looking at ways to get them into Switzerland." Tompkins pointed to David's glass. "You've not had a chance at your Port. Let's take a break and let this information sink in. Are you familiar with Stilton?"

"Yes, I've had some in the dining room. It's a bit like Roquefort, but drier and less complex."

"I don't know Roquefort."

"Roquefort's made from ewe's milk. It's named after a small town in the south of France where it's made. One of my mother's favourite cheeses... And mine. It has the same blue veining as this, but it has a much more complex flavour and a finesse. It's would be akin to comparing toad-in-the-hole to bœuf en croûte."

"I recall reading that your mother's from southern France and that you're also fluent in French. What's beufen croot?"

"Seared beef tenderloin spread with a layer of mousse de foie gras and cèpes duxelles, then wrapped in a thin pâte brisée and baked."

"The French certainly look at food differently than we British. You must miss it."

"Oh. for sure. I enjoyed some better dining in Belgium. Our fall-back area at Ypres was next to the French one, so I visited them often." He smiled and picked up his glass, nosed the wine and took a sip. "Sweet. Rather pleasant, actually. Tell me about this."

"That's right, You haven't had your first Mess Dinner yet. That's the fifth week. The Port traditions will be introduced then. The origin of Port is a strange story. It's from Portugal, but it was invented, or at least designed by the English. During the Restoration after the Civil War, King Charles imposed heavy taxes on French wines, so the merchants turned to Portuguese wines."

"Yes, I recall from my studies on international commerce that England and Portugal had continuous trade treaties going back to the Middle Ages." David nosed his wine again and took another sip. "Seems to be high alcohol."

"Yes, brandy was initially added to the casks to fortify the wine for the long, rough sea voyage. They later refined the method by adding the brandy earlier in the process to kill the yeast and stop the fermentation. The unfermented grape sugar gave the sweetness the British palate craves."

"So the small glasses are because of the high alcohol, then. To limit the amount." He nosed his wine again, then examined the glass. "There's probably a wonderful bouquet we're missing with these. There's an amazing difference between the same wine in a small glass and in a larger one."

Herman looked at the two of them and shook his head. "Not had wine before I arrived here. Nothing but lagers and ales before."

"You'll have plenty of opportunities to get to know great wine. We'll be working at a winery as our cover in Switzerland."

"How do you see that being set-up?" Tompkins asked.

"My aunt has a pasture that abuts the border, and she wishes to prepare it for planting to vines. I figured the work of peeling off the sod layer of weeds and grasses and preparing the underlying soil will provide great cover for the sappers to do their tunnelling. Their tailings will go unnoticed among the other work." He laughed. "Actually, their tailings will improve the vineyard soil. The land has a broad streak of calcareous marl which is superb for the Pinot Noir and Chardonnay she'll plant. The sappers will bring more of this to the surface for us to spread. We'll all win."

"And your aunt... She's the great aunt of whom you spoke?"

"Yes, British-born. She emigrated to Switzerland in the late 1870s, following the earlier lead of her sister, my grandmother. They're all eager to do what they can for the war effort."

Tompkins put his glass to his nose. "So you say this would be more enjoyable in a larger glass."

"I think much more. We'd be able to see its complexities and its nuances."

"Let me wheel the trolley back to the pantry and return with claret glasses. I'll also see if I can find some walnuts. They go superbly with Port."