They set off an hour before dawn while the village slept, walking silently across the damp meadow grass at the side of the settlement and then up the same mountain path they had taken on the way to the little hermitage where August Jaeger had died.

The rain had stopped and the light, when it came, was grey and the peaks were shrouded in dark clouds. Most of the snow had now melted, save at great height.

Both of them wore strong boots and Paula had discarded her traditional woman’s costume for a pair of her late husband’s trousers, held tight at the waist with a belt and tacked up then secured with string around her boots. They both had ropes and axes, and Wilde had two holstered pistols, an M3 sub-machine gun strapped to his backpack and a pair of hand grenades in his jacket pockets.

Their route took them past the hermitage. When they saw it, Wilde decided it was worth a short detour and climbed up the steep stone steps alone while Paula waited below. He walked through the little house and chapel in the lee of the rock face, in case something had been missed. The place had been left undisturbed by the French military. All that had changed was that the body and body parts had been removed. To the French occupying force, this was a crime of little interest, an argument among their enemies. No one cared that a man had died, nor were they interested in the identity of the killer.

He rejoined Paula and they carried on, past the little lake to the high mountains beyond. The path she chose was hard. For most of the trek, they were above the treeline and the grass was becoming sparse. The rocks were jagged and grey and, in places, loose and deadly. Every half-hour they stopped and studied the map together, and she pointed out their location. Progress seemed grindingly slow.

Paula had been worried that the weather would deteriorate, but the clouds had cleared and they were walking in full sun which, in a way, was worse. In his jacket, with his pack and weapons on his back, Wilde was drenched in sweat. The M3 was a lightweight weapon compared to other sub-machine guns, but carried uphill for hours on end its weight took a toll.

They made frequent stops to drink water and their canteens soon emptied and had to be refilled from ice-cold streams, which only served to burn the throat.

More than seven hours later, they came to a high ridge of sharp-spiked rock, a razor’s edge of a crest.

‘I think we’re just about there, Professor Wilde.’

He raised an eyebrow. He couldn’t believe anyone could live here or even close by.

‘Look over the ridge. If the map is right, you will find a self-contained valley below, with a small lake and a house.’