‘Oh yes, buddy. This is American territory. No ersatz acorn stuff in here. Come and sit yourself down.’

He indicated a leather sofa close to the window, then picked up a pen and notepad from his desk. In small letters he wrote, ‘Keep talking domestic stuff, OK.’

‘Then yes, coffee for me. What a swell office, Jim. I guess you live the high life here.’

‘You’d be amazed. More diplomatic parties than you could imagine. Of course some missions are missing, but that means more wine and eats for the rest of us.’

As he spoke, he had handed Wilde a couple of sheets of foolscap paper with dense writing in black ink.

‘Sounds like a good time.’

‘Tell you what, Tom, I’ll just leave you for a couple of minutes while I seek out that coffee. You sit here and read The New Yorker – we get it shipped in with the pouch.’

There was no magazine, not that Wilde could see anyway, just the two sheets covered in Vanderberg’s neat handwriting. It was a hand that Wilde had known as well as his own since their days rooming together at Chicago half a lifetime ago.

Vanderberg left the room with exaggerated footsteps and a firm closing of the door. Wilde began to read.

Tom, we can’t talk. We are pretty sure they hear everything we say since we moved here a couple of years back, so be on your guard not to mention Britain or Lydia or Cambridge. You have to remain Tomas Esser, American motorbike manufacturer. This paper you’re reading has only just been written by me and no one else has seen it, nor will they. I will burn it as soon as you have read it, so memorise everything. OK, this is what it’s about: you will have been told to collect a package. Well, buddy, I have to tell you that the package is, in fact, a ten-year-old girl born Klara Wolf, now known as Klara Rieger. No one outside Germany except FDR and Bill Donovan know of her existence. Not even the COI guys in London – which is why you could not be told the whole truth about your mission.

Klara Wolf is an important young lady, although she almost certainly doesn’t know it. She is presently living in a village near Berlin and, unknown to her or her adoptive parents, is in grave and imminent danger. The reason for this goes back ten years to her birth in a village named Braundorf in Upper Austria, not far from the German border. According to her birth and baptism certificate – and I have a copy of this in the safe – her mother’s name was Angelica Wolf. This was not true: her mother’s true name was Angela or Angelica Raubal. Her father was not named, merely marked down as ‘soldier, absent’.

Angelica Raubal was always known by a shortened version of her name, Geli. She was a niece of Adolf Hitler, the daughter of his half-sister, who is still alive and is also called Angela. Geli was much favoured by Hitler for several years in the late 1920s and early thirties, to the extent that she went to live with him in his Munich apartment, with a room of her own. They spent a lot of time together – picnics, opera, the whole thing. Almost certainly bed, too.