She looked at me for a moment longer – looked deep into me – then she nodded and turned to stare out of the window. The afternoon sun was a band of rose-gold light beneath the clouds. It shone warmly on her brow, her nose, the strong bones of her cheeks and chin. For a moment, she looked like the sister I remembered.

‘I need to go out for a while,’ she said.

‘It’ll get dark soon, Mags.’

‘I know, but I shouldn’t be too long. And Grandpa Joe will be home any minute.’ Then she winked at me. ‘Stay right here, Pet.’

I smiled. Where else could I go?

An hour or more passed. It was dreadfully lonely up there, and dreadfully cold too. The tide was high but starting to drop now. The shape of the Wyrm twisted beneath the waves like a ghostly serpent. It was hungry. I became aware of a faint, high note buzzing in my chest – the song of the stones – a warning . . . Then, as I looked at the sea, I thought I saw something else – in the deeper water beyond the sandbank. A long, dark shadow. I squinted at it through Pa’s telescope but it was no use – it was getting too gloomy to see anything clearly now.

As night closed in on the Castle, it began to rain – heavy drops hammering on the lighthouse roof and strafing the windows – and I wished with all my heart that Grandpa Joe would come home. What can have happened to him? There was a dogfight happening several miles out over the sea – I could hear the whining of the engines and the rattle of the guns. Every now and then there were showers of light in the sky – firework-bright. The feeble wail of the village air-raid siren seeped in through the edges of the windows, but I knew that I couldn’t get down to the coal cellar by myself.

Perhaps Dover has been bombed, I thought. Perhaps that’s why Grandpa Joe hasn’t come home. But then I shook the thought from my mind. I can’t start thinking like that, not when I am all alone here in the dark – I’ll drive myself mad. I closed my eyes and started counting, promising myself that either Mags or Grandpa Joe would be back by the time I got to one hundred.

But I didn’t get to one hundred.

The darkness of the lantern room and the sound of the rain somehow cocooned me. The violence of the world outside was so muffled and so very, very far away . . . My mind slipped sideways into a dream of underwater shadows . . .