A white box made of card lay in my hands, looking quite plain, quite unremarkable, yet I couldn’t help but hope that this was the key to how and why Lorelei had died. The key to getting Nick released.

It was about the size of a dinner plate, ten centimetres tall, without a single mark on it to denote its contents. I lifted the lid. It tipped up to reveal that the box was divided into a dozen identical little segments – but, crushingly, whatever had once been in those compartments was now gone. The thing was empty and meaningless.

I was about to cast it aside in anger when something struck me, though: a sense that there was something familiar about the box, something that I recognized. I was sure that I had seen one like it before. And yet I couldn’t think where.

It had been years ago, I was sure of that – when I was younger, although not a child – but when? Where? I racked my brains trying to remember more.

It was the clamour of a police-car bell outside that made me stop. Nervous, I eased back the curtain and looked out the window. The car came close to the house, charging through the ruts and black water, but continued straight past without slowing. It wasn’t coming here – but, my God, what they could do to us just with the sound of a bell.

I returned to the box, weighing it in my hand and trying to picture another like it. I paced thoughtfully around Hazel’s room, surrounded by her books; the pictures on her wall; the soft pink ballet shoes tied to the back of her door; her navy school skirt and blouse slung over the back of a chair. I could have kicked myself for not being able to remember. The dank house, it was as if it were taunting me. Then I halted and looked back at the chair.

That uniform. I stared at it. And suddenly I was back in another time, a time when I had worn a muddy-brown uniform, my feet damp even through thick leather boots as thin rain drizzled down. Yet a thrill of excitement was running through me as I looked along the barrel of a bolt-action rifle. I and twenty other girls were all lined up for our Compulsory Basic at a run-down former naval base in Kent and I reached into a carton just like this one to lift out a round, before slotting it into the breach and squeezing the trigger. Then came the explosion and a kick into the muscle of my shoulder. Followed by the dark, distant hole appearing in the target.