Anticipate, Nightingale had drilled into me, formulate, release . . . and for god’s sake, Peter, you have to have the follow-up ready the moment you release the first spell.

I had anticipated the charge and I was speaking the spell even as splinters of wood clattered off the ceiling. It was my shield, famously capable of stopping seven out of ten pistol calibre rounds – on a good day. Had the beast hit it face-on, that horn would have gone right through it. But I didn’t have it held face-on – I had it deflected at an angle so that the point slid off to my right, because the surface of the shield is well slippery.

And I knew that not from some ancient text but because I’d logged hours on the range, conjuring the thing at different angles while Molly poked at me with a stick.

The thing bellowed with rage as its horn slid uncontrollably to its left. And where the horn went, head, neck and shoulders were sure to follow. It hit the kitchen table at just over knee height and went down on its side amidst splinters of laminated chipboard. Its great hooves scrabbled on the lino as it tried to get them back under itself. But I had my follow-up ready – I twisted and swung Hugh’s staff as hard as I could. I would have liked to have landed one on its head, but my reach wasn’t good enough and instead the staff’s iron cap scored its way down the unicorn’s shoulder.

It bellowed with pain and frustration.

Cold iron, I thought. The stories are true.

I hit it again and it screamed.

I kept the shield aimed downwards to keep it pinned and raised my staff once more.

The unicorn stopped struggling to rise and lay there quivering, staring at me with a mad brown eye – in the darkness it seemed real and solid and all there.

‘Are you going to be a good boy?’ I asked.

The mad eye rolled in its socket, but the head slumped down amongst the splintered wood of a kitchen unit, stainless steel cutlery and the remains of Joanne’s best china.

‘Dominic,’ I said. ‘Are you still there?’

‘Yeah,’ he said. ‘That was interesting.’

‘We’re going to be stepping back into the hallway,’ I said. ‘Give Princess Luna here a chance to get up.’

Dominic put his hand on my shoulder and guided me backwards – as I went, I lifted the shield away from the unicorn, although I made a point of keeping it between me and the beast.