‘Ah. One of her other relations,’ she’d said. ‘I asked not his name, but she knew who he was.’

Which, I thought, to give her credit, was a truthful answer. She had not asked Father Archangel his name, for she’d already known it, and the little girl herself had recognised that he was Colonel Graeme’s son. My admiration of the Abbess Butler had grown even stronger when I’d realised how she’d managed to hold off the ‘priests’ without having to compromise her honesty.

I was still thinking of this when Rob started the car and reversed neatly out of the parking spot.

I asked, ‘Were they really priests, do you think?’

‘Oh, I doubt it. They probably worked for, or with, that girl’s English spy.’

‘Christiane’s boyfriend.’ I frowned.

‘Aye. She finally found something useful to tell him,’ he said with a shrug.

‘Well, I hope it was worth it.’ My voice came out darkened with sarcasm. ‘Using a child like that.’

‘Anna got careless. She made a mistake. She’d been warned not to share all the things she’d been told.’

‘She was only a child,’ I defended her. ‘And she’d been promised the convent was safe. She thought all the bad people, the “bad men”, were English, and came from outside. Christiane was like her – she was Scottish, a girl, and she lived in the convent, so why wouldn’t Anna have thought it was all right to talk to her? Honestly.’

Rob’s sidelong glance made a point. ‘See? You’re getting attached to her.’

‘It was a rotten thing Christiane did,’ I said, ‘taking the trust of a child and betraying it.’

Rob, more forgiving, or possibly just more pragmatic, said, ‘Aye, well, she did it for love. Love can make people do mad things, sometimes.’

As we crossed over the next road, the pale Menin Gate rose beside us on Rob’s side, but through my own window I caught a swift glimpse of the old market square where we’d eaten last night. Just a glimpse, but enough to make note of how different it looked in the grey early morning, the funfair shut up and forgotten, the lights and the sound and the magic extinguished by daylight.

I thought of my unicorn, riding along in the boot, and a part of me – only a part, mind – forgave Christiane just a little, for wanting so badly to win back the love of her Englishman. Maybe she had.

It was not a long drive to Calais.

I’d been through it a dozen times, mostly by train, but I’d never once stopped to look round, or to think of the town being anything more than the end of the Chunnel – a touristy transport hub crowded with ferries and coaches.

‘And refugees,’ Rob added, as we approached from the south, up a boulevard edged with young trees and mansard-roofed buildings with bright-red brick walls. ‘People wanting to get clear of all the wars in their own countries pay the traffickers and wind up here in migrant camps or worse, in the hopes they’ll find a way to get across the Channel into England.’

A hard life, to be sure, and I was silent for a moment while I thought about the desperation that drove people to abandon their own country, their own home. I said, ‘It’s sort of the reverse of what the Jacobites were doing, then, in Anna’s time. I mean, there would have been a lot of people coming over from the Scottish side …’

‘And England,’ Rob put in. ‘Some travelled south, and came through England in disguise. Wherever they could find a boat to bring them over.’

‘But they were just refugees as well, escaping war.’

‘The aftermath of war, more like,’ he said. ‘The persecution. When the 1715 went wrong, the English got their own back. Anyone who’d had a hand in it was hunted, fined, imprisoned, stripped of what they owned and loved. A lot were hanged.’

I thought of Anna’s Uncle Maurice, and his worry for his brothers left behind in Scotland, one imprisoned, one too ill to flee, and wondered whether they’d survived that time of treachery.

‘The English,’ Rob said, ‘would have had their own spies in Calais and paid informers with the Jacobites, reporting back who came and went, and why. No doubt the colonel’s son, the monk, was doing much the same thing for King James.’

‘Wouldn’t that be against his vows, or whatever?’

‘He was a soldier first.’ Ignoring the grand, impressive town hall building we were passing on his side, Rob glanced across and out of my window at a tall stone column that appeared to be some kind of war memorial, carved round with sculpted images of sacrifice and valour. ‘Whatever vows he took, I doubt he could stand by and not take sides.’

A little further on we crossed a broad canal and at the far side of the bridge Rob slowed, and swung us through the roundabout, and in a sudden moment of decision made a right turn at the corner of a park onto a very narrow street that ran along the park’s north edge. On my side of the car, a rather uninspiring row of flats stood solidly in line along the pinkish pavement, some with weathered balconies that overlooked the trees and greenery stretching to the right of us. The flats gave way to a low red-brick building, and Rob reverse-parked at the kerb just across from it.

I looked at the sign on the building, and then at Rob. ‘The Musée des Beaux-arts? Are we going in?’

He shook his head.

Glancing past him to the park, I guessed again. ‘We’re having a picnic.’

‘No.’ He grinned, and opening his door got out and stretched his shoulders. We’d been on the road for just under two hours – not that long, by Rob’s own reckoning – so I assumed the stiffness he was showing came from having sat outside for half the night, with me asleep against his shoulder, more than from this morning’s driving. He recovered quickly, though, and by the time I got my own door open he was there to hold it for me.