There has been a lighthouse above Stonegate for centuries – to warn ships of the dangerous sandbank in the sea beyond the cliffs, and to guide them safely past the Wyrm to the harbour below. Its light has come from all sorts of different things, from oil lamps to braziers and coal fires. It hasn’t always looked the same, of course, but I was pretty sure that it had never been painted green before. The lighthouse has been destroyed many times. It has been hit by hurricanes, struck by lightning and burnt down by fire, but it has always risen again – a phoenix from the storm-blown flames.

I love our lighthouse, and I couldn’t imagine living anywhere else, but I know that other people often find it odd. They might imagine, perhaps, that all the furniture has to be round in order to fit inside, or that we sleep in hammocks hung from the spiral staircase, and spend our days climbing ladders and polishing glass. Actually, there is a fair bit of glass-polishing that has to be done, but we have never slept in hammocks: we sleep in normal beds in the cottage at the foot of the lighthouse. The cottage is just like any other cottage really, like any other home. And we are just like any other family. At least, we were just like any other family, before the war began. Now, if I think back to that sunny autumn day when we finished painting the lighthouse, I can see that the tide had already begun to turn.

It was beautifully warm for September, and Mags and I lay next to each other in the long grass between the standing stones.

‘Looks odd, doesn’t it?’ Mags said. ‘Now that it’s green.’

‘It looks weird,’ I agreed.

I loved our strong, white tower – brilliant and proud against a clear blue sky. It looked so different now that it was the same sort of earthy colour as the fields that surrounded us. It looked as if it had sprouted up from the ground itself.

‘It looks like a goblin castle,’ I said.

Mags laughed. ‘Or an ogre’s folly.’

‘Or a troll’s tower.’

My sister plucked a daisy and threw it at my face. I laughed too and closed my eyes. My muscles were achy from painting, and the grass was warm and dry and pleasantly scratchy beneath me.

‘It makes sense, though, doesn’t it?’ Mags said in a more serious voice. ‘Hitler’s bombers won’t be able to spot us as easily now. Pa said there is a risk that landmarks like lighthouses could be used by German planes for navigation.’