I climbed to join him. It was harder than I’d thought, to climb that deeply shifting dune, and I did it ungracefully, but Rob seemed too absorbed to take much notice. He did shift aside, though, in the level spot where he was sitting, to make room for me as I collapsed beside him. We were in a sheltered hollow with the wind-shaped sand and blowing grasses rising gently to each side of us and shielding us behind.

Rob took the cup of now-cooled tea I handed over to him. ‘Thanks.’

‘You’re welcome.’ I cradled my coffee and looked to the beach as well. ‘What are you looking at?’

‘Just what you see.’ When he lifted the takeaway cup for a drink I could see a faint smile touch his mouth at the corners. ‘But afore you came,’ he told me, ‘I was watching Margaret’s Anna.’

I still found it difficult to tell if he was teasing me. I had to ask, ‘You’re serious?’

‘Dead serious. Just there.’ He gave a nod towards the empty beach. ‘I’d no idea it was her at first, ye ken. It was the woman I was watching.’

He had lost me now. ‘What woman?’

‘Sorry.’ I could see the effort that it took for him to organise his thoughts into an order that allowed him to explain.

He started at the moment when he’d woken with the sunrise to a pressing sense of restlessness. Not wanting to disturb my sleep, he’d fought it for a while, but when the urge to get outdoors had overwhelmed him he’d gone down himself, alone.

‘I left you breakfast.’

‘Yes, I ate it. Thanks.’

‘No problem. I was thinking,’ he admitted, ‘I might walk up to the castle, have a look around.’

‘Without me?’

‘Well, I would have gone again, when you had wakened. But the pull that I was feeling was so strong. It didn’t take me to the castle, though,’ he said. ‘It brought me here.’

I looked along the ridge of dunes, deserted but for us. ‘What did it feel like?’

‘I no ken.’ He sifted sand between his fingers with a shrug. ‘A kind of longing, like, if that makes any sense.’

I felt an edge of it myself, I thought, and found my own gaze drawn far out towards the distant line where sea met sky, as though there might be something there for me to see, that I’d been waiting for. But what, I didn’t know.

Rob said, ‘And then I saw the woman. She came down that hill, just over there.’ He pointed to the headland by the harbour to our left. ‘And at the bottom of the hill she stopped a moment, as if she were feart to take another step, but then she finally came across, and passed just underneath here, and I realised what she was.’

I had a sense of that as well. ‘A ghost?’

He gave a nod.

‘And did you speak to her?’

‘There’d have been no point, she’d not have heard me.’

‘But,’ I said, ‘your Roman ghost, your Sentinel – you talk to him.’

His glance slid sideways to me as he raised his tea to drink again. ‘The Sentinel’s a spirit. All that made him what he was in life, he has that still, it’s just that he no longer has a body. But this woman, she was nothing like the Sentinel. She was more of a shadow,’ he said. ‘A residual ghost, is the way they’re described, I think. Something happens in a place, ye ken, that carries deep emotion, and it leaves such an impression that the shadow of the person keeps repeating it forever. If you have the eyes to see.’

She’d been an older woman, so Rob told me, with an almost regal grace that had intrigued him, and her clothes had clearly marked her as a woman of another time, her long gown dragging heavily across the tide-wet sand yet leaving no trace of a trail, just as her feet had left behind no footprints.

And because he’d been intrigued, he’d set his focus on her, trying to see back in time to when she’d been a person, not a shadow.

I still wasn’t sure how Rob saw things, when he looked back, but from what he was saying I gathered that, while I could only see a narrow window on the past, he saw the whole of it.

He’d seen the older woman walking past. She’d walked a little further on before she’d stopped and, looking up, began a conversation with a younger, bright-haired woman sitting partway up the dunes. He might have listened in, had his attention not been stolen at that moment by a burst of childish laughter from the beach.

‘There were five children,’ Rob said. ‘All one family, from the look of it, though not a one was over ten years old. And the youngest of them, she’d have only been this high.’ He held his hand above the sand to show me. ‘Small, ye ken, still walking on her toes, the way they do. But she could run.’

He painted me a picture with his words till I could see her too: the tiny girl with windblown brown curls running with her brothers and her sisters and a giant mastiff dog who seemed to take delight in teasing her to try to take the stick he carried in his mouth. But when she’d run too closely to the waves in her pursuit, both of the women who were playing with the children had gone after her, and one of them – her mother, Rob assumed – had called her: ‘Anna!’

When the little girl had failed to stop, the woman had put on a burst of speed herself and caught the child and, lifting her, had swung her in a wide and joyful arc of skirts and water spray and in delight the little girl had laughed with such abandon that it made Rob smile himself, though he was watching from a distance of some centuries.