She took his hand and smiled at him, then took a step back and gave a smart straight-arm salute. He laughed out loud and he and his companion saluted her back. At last the senior man seemed to notice Wilde.

‘Herr Sable – Monsieur Sable – vos papiers, s’il vous plait.’

Wilde’s heart sank; the officer spoke French. He would be found out in an instant. Wilde glanced at Sunny, whose eyes were wide with apprehension but whose mouth was smiling. He looked back at the officer and gave a sharp, submissive bow of the head, loosening his grip on the knife and removing his hand from his pocket. He brought out his papers and handed them over for inspection. The officer studied them carefully, then handed them to his junior officer, who took an age comparing the picture with Wilde’s face. At last he nodded and passed them back.

‘You understand we have to be sure of these things,’ the officer said, reverting to German. ‘I believe Frau Somerfeld has told you whose estate you are entering?’

‘Yes,’ Wilde said, happier at the language switch and the realisation that the two men were not SS after all, but Luftwaffe officers – air force. The winged insignia on their uniforms made that clear. Still frightening, yes, but the Luftwaffe was not renowned for employing the callous cruelty of the SS.

‘And you speak a little German? Good, good. Come, let us get you to the house. You all look as though you need food and rest. Frau Göring has said you are to be looked after.’

*

Was this really happening? Were they being escorted into the centre of Hermann Göring’s country estate by two amiable air-force officers? Wilde began to wonder if he had fallen down a rabbit hole and entered a particularly alarming dreamworld. The walk was only ten minutes, but in that time, he spotted a sniper in a camouflaged tree house, covering the small group with a high-powered rifle, and saw a small herd of bison that looked as though they would have been more at home on the Great Plains of North America than the forests of northern Germany.