It was my favourite sort of weather – breezy and cool but gloriously bright. We made for the sunny, seaward side of the lighthouse, and Mutti spread blankets out on the rabbit-nibbled grass. Mags followed a few minutes later. I had managed to entice her from the bedroom by reciting a list of all the wonderful food we were about to devour without her, so she tagged along, but I could tell that she was still upset with Pa.

We tucked into the sausage rolls and hot cocoa straight away. It didn’t take too long for Mags to defrost – after all those mornings of margarine scraped over a thin slice of wheatmeal toast, who could have resisted a breakfast banquet like this?

‘I haven’t forgotten about the lifeboat station, Mags,’ Pa said to her quietly, when he didn’t think anyone was listening. ‘We’ll go tomorrow. All right?’

‘All right,’ Mags said after a moment, giving Pa one of her sideways smiles. Then she shoved an entire scotch egg into her mouth, and I thought I was going to die laughing.

I will always remember that morning. I couldn’t have known it at the time, but it would become the last, truly happy memory I have of all four of us together. It was as if the tensions and distrust of the past few months had been washed away, and we were as we’d been before the war began. How I wish someone had taken a photograph of us – Pa with his arm around Mutti’s shoulders, Mags spraying crumbs everywhere as she laughed, the Daughters of Stone standing like sentinels around our little family and, above us all, the enormous spring sky, as blue as a balloon and bursting with promise for the summer ahead.

But then again, I don’t really need a photograph, do I? I can see it all perfectly whenever I want. I just have to close my eyes.

‘Tell us the story, Frederick,’ Mutti said.

‘The story of the Wyrm and the Stones?’

‘Yes.’

So he did. We gathered close, and Pa told us about the fog and the fishermen, and the four daughters who sang to the sea, promising the greatest of sacrifices if it would only bring their fathers safely home. When he got to the bit about the Wyrm spitting out the boat and devouring the souls of the daughters instead, I couldn’t help shuddering – just as I had when I was four years old.