It was starting to grow dark when the train arrived. Anton, who had expected cattle and mud, was surprised to find himself in a cobbled square, next to a well-kept Rathaus and streets laid out in the bend of a river. A taxi took him to the retreat: a pink-washed house, perhaps a hundred years old, that stood on the side of a hill next to a vineyard, where half the rows of vines had been grubbed up. He went through some wrought-iron gates and across a gravelled terrace towards the front door. To his left, at a lower level, was a paddock in which two horses were grazing. Before he could pull the bell, the door opened and a maid beckoned him in.

‘Thank you. I’ve come to—’

The maid lifted her finger to her lips. He followed her upstairs, along a dark corridor, down some steps and eventually into an end room that overlooked the gates. It was like a quarantine, he thought – or perhaps he was the only man in the building.

Speaking quietly, the maid said, ‘I’ll come for you at seven and take you to meet Fräulein Hartung. There’s a bathroom over the way there.’

There was a crucifix above the bed and half a dozen religious texts between bookends on a chest. Otherwise, the room was bare. Anton opened the window onto the terrace and heard one of the horses snorting in the paddock below. He found the bathroom, washed and changed his clothes, then went back and settled down to wait.

The maid arrived promptly and gestured him to follow. On the ground floor, they went along a wood-panelled corridor at the end of which the maid knocked on a closed door. The woman who opened it dismissed the maid and turned to Anton.

‘Herr Heideck? We have dinner in half an hour, but we can talk now. I’m Claudia Hartung. Is your room all right?’

‘Yes, thank you. It’s good of you to see me. This is all a little … unexpected.’

‘I suppose it is. Still, we must try to do the right thing. Do sit down. When did you last see Delphine?’

Claudia Hartung had a bun of orange hair and glasses with smears on the lenses. She sat at a desk with shelves and a metal filing cabinet behind her; there was a sofa beneath the window, which looked over a backyard. Anton took a chair opposite the desk.

‘I last saw her in the summer of 1914. Nearly twenty years ago. We had lived together near Vienna. I went to Paris for work. When I finally got back, I could find no trace of her. I assumed she’d gone home to France. Or perhaps she’d met with some accident. It was odd that she left no letter. The trouble was, I couldn’t carry on making inquiries because by then I was in the army. I had no time to myself.’

‘Shall I tell you the facts as I know them?’ Hartung had a metallic voice, pitched rather high, though not tuneless.