All I knew was that I needed the end of that story, that I needed to be the one who brought it home, and that I was frightened. I don’t scare easy, but just like Daniel, I’ve always known that there’s a price to pay. What Daniel didn’t know, or didn’t mention, is what I said right at the beginning: the price is a wildfire shape-changing thing, and you’re not always the one who chooses, you’re not always allowed to know in advance, what it’s going to be.

The other thing hitting me over and over, with a horrible sick lurch every time: this could have been why she had come looking for me, this could have been what she had wanted all along. Someone to change places with her. Someone longing for the chance to toss away her own battered life, let it evaporate like morning mist over grass; someone who would gladly fade to a scent of bluebells and a green shoot, while this girl strengthened and bloomed and turned solid again, and lived.

I think it was only in that moment I believed she was dead, this girl I had never seen alive. I’ll never be free of her. I wear her face; as I get older it’ll stay her changing mirror, the one glimpse of all the ages she never had. I lived her life, for a few strange bright weeks; her blood went into making me what I am, the same way it went to make the bluebells and the hawthorn tree. But when I had the chance to take that final step over the border, lie down with Daniel among the ivy leaves and the sound of water, let go of my own life with all its scars and all its wreckage and start new, I turned it down.

The air was so still. Any minute now, I would have to go back to Whitethorn House and do my best to wreck it.

Out of nowhere I wanted to talk to Sam so badly it was like being hit in the stomach. It felt like the most urgent thing in the world, to tell him, before it was too late, that I was coming home; that, in the ways that mattered most, I was already back; that I was scared, terrified as a kid in the dark, and that I needed to hear his voice.

His phone was off. All I got was the voice-mail woman telling me, archly, to leave a message. Sam was working: taking his turn surveilling Naylor’s house, going through statement sheets for the dozenth time in case he had missed something. If I’d been the crying type, I would have cried then.

Before I understood that I was doing it, I set my phone number to Private and dialed Rob’s mobile. I pressed my free hand flat over the mike and felt my heart going slow and hard under my palm. I knew this was very possibly the stupidest thing I’d done in my life, but I didn’t know how not to do it.

“Ryan,” he said on the second ring, wide awake; Rob always had trouble sleeping. When I couldn’t answer, he said, with a sudden new alertness in his voice, “Hello?”

I hung up. In the second before my thumb hit the button I thought I heard him say, fast and urgent, “Cassie?” but my hand was already moving and it was too late for me to pull it back even if I had wanted to. I slid down the side of the tree and sat there, with my arms wrapped tight around myself, for a long time.

There was this night, during our last case. At three in the morning I got on my Vespa and went down to the crime scene to pick Rob up. On the way back the roads were all ours, that late, and I was going fast; Rob leaned into the turns with me and the bike barely seemed to feel the extra weight. Two high beams came at us around a bend, brilliant and growing till they filled the whole road: a lorry, half over the center line and coming straight for us, but the bike swayed out of the way light as a stalk of grass and the lorry was past in a great whack of wind and dazzle. Rob’s hands on my waist shook every now and then, a quick violent tremor, and I was thinking of home and warmth and whether I had anything in the fridge.

Neither of us knew it, but we were speeding through the last few hours we had. I leaned on that friendship loose and unthinking as if it were a wall six foot thick, but less than a day later it started to crumble and avalanche and there was nothing in the world I could do to hold it together. In the nights afterwards I used to wake up with my mind full of those headlights, brighter and deeper than the sun. I saw them again behind my eyelids in that dark lane, and I understood then that I could have just kept driving. I could have been like Lexie. I could have hit full speed and taken us soaring up off the road, into the vast silence at the heart of those lights and out on the other side where nothing could touch us, ever.

21

It only took Daniel a couple of hours to come up with his next move. I was sitting up in bed, staring at the Brothers Grimm and reading the same sentence over and over without taking in a word of it, when there was a quick, discreet rap on my door.

"Come in,” I called.

Daniel put his head in the door. He was still dressed, spotless in his white shirt and shining shoes. “Do you have a minute?” he inquired politely.