Bern, Switzerland — Sunday 14 November 1915

David manoeuvred the lorry into the courtyard of the Ambassador's residence in Bern at five to eleven on Sunday morning. The butler opened the door to his knock. "They are waiting for you in the drawing room, Sir. Leave your bag here, I'll have it taken up. You head in, I'll inform the Ambassador and your wife you've arrived."

Colonel Picot and John Wallinger greeted David as he entered and Picot immediately asked him for details.

"I think it best to wait for the Ambassador, but I will tell you we're selling lots of potatoes. More than three and a half tonnes so far. We blend in well. Many sympathisers are now crossing the border with produce. I don't think any of the others are using it for cover, though." David laughed. "But how would I know? It's such a great disguise."

"What's a great disguise?" Evelyn Grant Duff asked as he crossed the room toward them. "You're looking anything but military. Is that the disguise?"

"No, Sir. Selling potatoes in the German markets."

"Clever idea, that." He smiled as he shook David's hand, then his face turned serious. "But that's not why you telephoned me last evening. Tell us about it."

David related the details he had been told of Herman's disappearance and of the attempts to find him. "Two are in there now, both skilled climbers and very serious. I'll be meeting with them mid-afternoon tomorrow in Titisee, giving them another two full days to comb the area. We all think he had fallen. It's very steep and rugged through there, and the nature of the rock, gneiss, makes the cliff faces unstable. Rocks could have fallen on him or a foothold may have given way."

"And what if he had been spotted on the canyon side and apprehended?" Picot asked.

"Herman would keep his mouth shut. He wouldn't betray us or the mission, no matter what they threatened." David closed his eyes and winced as he thought of the French officer who had been emasculated. "Herman'd hold true."

"Nine days since he was last seen. That's a long time for him to lay injured." Evelyn said.

"Hans said that from his food remaining, it seems Herman disappeared on the fifth or sixth day. That would be Tuesday or Wednesday. We were to have met at the market on Thursday, so it appears to have happened a day or two before Hans went in to search."

"Seems everything possible is being done while still remaining covert," Wallinger said. "To do more would risk exposure." He paused for a moment, then asked, "What of your intelligence gathering? Did your men find any vulnerabilities?"

"On each of the three lines." David smiled as he saw relief on the faces. "Hans reported the cliffs above the rack rail section of the Höllentalbahn are almost entirely gneiss and are riddled with cracks and fissures, which seem to be waiting for the placement of our explosives. When we drove through the narrow canyon yesterday, Georg pointed to several masses of rock we could easily collapse to bury the tracks under ten or more metres of rubble..."

"Georg, That's Sergeant Heiss?" Picot asked.

"Yes, Sir. We dispensed with ranks and anything else military while we were training in Oxford. Safer that way now."

"Yes, certainly. So the other two lines?"

"Above the tunnel-intensive section of the Schwarzwaldbahn, Franz found a massive detached granite slab just waiting to be sent down the slopes. He calculates the slab alone at over two thousand tonnes. It will without doubt gather that much or more to accompany it as it goes."

David smiled inwardly at the knowing nods, then he continued. "The Sauschwänzlebahn, the Pigtail Line has soldiers posted at every bridge, viaduct and tunnel. Both ends of each and encamped under the viaducts. The line runs up through gently rolling open hills, with the rise to the pass being too steep for trains without extensive engineering, so the route twists and curls through switchbacks and tunnels and across enormous viaducts to ease the grade. The vulnerable spots we identified from the maps, the drawings and the photographs are all heavily guarded. There's no way to approach them unseen."

"But you said you had solutions for all three lines." Wallinger tilted his head.

"We're going to play a new version of billiards. Derail a train and send it careening into the tallest pier of the Biesenbach Viaduct and collapse the entire structure. It's over two hundred and fifty metres long and the tallest pier is more than thirty metres in height. It will take them many months to restore traffic."

"Your timing of these? When do you anticipate doing it?" Wallinger asked.

"We had discussed doing all three simultaneously, but we thought it better to involve a heavily laden train in each. We must do that on the Pigtail Line, anyway. But all three of them within a few hours of each other. We still need to figure out train schedules."

David reached into the breast pocket of his jacket, pulled out a piece of folded paper and handed it to Wallinger. "Here's a list of the explosives, blasting caps and detonating cord we'll need. We've about two weeks to assemble it. The Sappers passed the half-way mark on Thursday, and Sergeant Perrier estimates breaking through the floor of the far tool hut on the twenty-ninth."

"That's moving more quickly than anticipated," Picot said.

"They're still in soft chalk, and he expects it to continue all the way. I'm amazed by the confidence he has with his direction and distance. He says it's merely a matter of accurate sighting, measuring and calculating."

Evelyn pursed his lips and nodded. "I've had the kitchen informed you'll all be joining us for lunch. Let's relax now and let these topics drop before we meet the women." He smiled at David. "Maria has been relaying reports of a splendid vintage at Sonnenhang." Then motioning toward the door, he continued, "I'm sure you're eager to greet her. On your way. We'll see you both at half past noon in the dining room."