And as for my room . . . oh God . . . as for my room, that is one of the bricks in the edifice of evidence the police built against me.

“Why did you cover the security camera in your room if you had nothing to hide?” they kept asking me again, and again, and again.

And I tried to tell them—to explain what it’s like to be a young woman, alone, in a strange house, with strangers watching you. I tried to tell them how I was okay with a camera in the kitchen, the den, the living room, the corridors, even with cameras in the girls’ rooms. But that I needed somewhere, just one place, where I could be myself, unwatched, unmonitored. Where I could be not Rowan but Rachel—just for a few hours.

“Would you want a camera in your bedroom?” I asked the detective, point-blank, but he just shrugged as if to say, It’s not me on trial, love.

But the truth is, I did cover up that camera. And if I hadn’t, we might know what happened to Maddie.

Because, I didn’t kill her, Mr. Wrexham. I know I’ve said that already. I told you in the very first letter I sent you. I didn’t kill her, and you have to believe me, because it’s the truth. But I don’t know, writing these words in my cramped cell, with the Scottish rain drizzling down the window outside . . . Have I convinced you? How I wish I could persuade you to come here. I’ve put you on my list of visitors. You could come tomorrow, even. And I could look into your eyes and tell you—I didn’t kill her.

But I didn’t convince the police of that. I didn’t convince Mr. Gates either.

In the end, I’m not sure I even convince myself.

For if I hadn’t left her that night, if I hadn’t spent those hours with Jack, in his flat, in his arms, none of this would have happened.

I didn’t kill her, but her death is on my hands. My little sister.

If you didn’t kill her, who did? Help us out here, Rachel. Tell us what you think happened, the police asked, again and again, and I could only shake my head. Because the truth is, Mr. Wrexham, I don’t know. I have constructed a thousand theories—each wilder than the other. Maddie, leaping like a bird into the night; Rhiannon, coming back early from her night out somehow; Jean McKenzie, hiding in the attic; Jack Grant, creeping past me while I was waiting downstairs for Rhiannon.

Because Jack turned out to have secrets too, did you know that? Nothing as grand or melodramatic as what I had imagined—he wasn’t related to Dr. Kenwick Grant, or at least if he was, neither he nor the police managed to trace the link. And when I told the police about the hank of string in his kitchen and the Aconitum napellus blossom, he, unlike me, had a quick and reasonable explanation. Because Jack, it seemed, had recognized the purple flower sitting in the coffee cup on the kitchen table—or thought he had. And so he had taken it with him to compare it to the plants in the poison garden. When he discovered that what he had suspected was correct, that the flower in the kitchen was not just poisonous but deadly, he had removed my makeshift string barrier, and replaced it with a padlock and chain.

No, Jack’s deep, dark secret was much more mundane than that. And instead of exonerating me, it only piled up the evidence against me—adding to the weight of reasons I might have wanted to cover up my liaison with him.

Jack was married.

When they realized I didn’t know, the police took great delight in ramming the fact home, reminding me at every possible opportunity, as if they wanted to see me wince with pain afresh each time. But the truth was, I was beyond caring. What did it matter, if Jack already had a wife and a two-year-old back in Edinburgh? He had promised me nothing. And in the face of Maddie’s death, none of it seemed important.

I would be lying though if I said that in the days and weeks and months since I’ve been in here I haven’t thought of him and wondered why. Why hadn’t he told me about her? About his little boy? Why were they living apart? Was it financial—was he sending money back to them? If the Elincourts were paying him half as much as they’d offered me, it was more than plausible that he’d taken the job for money reasons.

But maybe not. Perhaps they were separated, estranged. Perhaps she’d thrown him out, and this offer of a job, with a flat attached, had been the perfect way to move on.

I don’t know, because I never had the chance to ask him. I never saw him again, after I was taken down to the station for questioning, and then cautioned, and then remanded in custody. He never wrote. He never phoned. He never visited.

The last time I saw him was as I stumbled into the back of a police car, still covered in Maddie’s blood, feeling his hands gripping mine, strong and steady.

“It’ll be all right, Rowan.” It was the last thing he said to me, the last words I heard as the car door slammed shut behind me and the engine started up.

It was a lie. A lie, from first to last. I was not Rowan. And nothing was ever going to be all right again.

But the thing I keep coming back to is what Maddie said to me that very first time I met her, her arms wrapped hard around me, her face buried in my top.

Don’t come here, she had said. It’s not safe.

And then, those last words, sobbed in parting, and later denied, words that I am still certain I heard, months later.

The ghosts wouldn’t like it.

I don’t believe in ghosts, Mr. Wrexham. I never have. I’m not a superstitious person.

But it was not superstition that I heard pacing the attic above me, night after night. It was not superstition that made me wake in the night, shivering, my breath white clouds in the moonlight, my room cold as an icebox. That doll’s head, rolling across the Persian rug, that was real, Mr. Wrexham. Real as you and me. Real as the writing on the walls of the attic, real as my writing to you now.

Because I know, I know that’s when I really sealed my fate with the police. It wasn’t just the fake name, and the stolen documents. It wasn’t just the fact that I was Bill’s estranged daughter, come back to exact some sort of twisted revenge on his new family. It wasn’t any of that.

It was what I told them on that first awful night, sitting there in my bloodstained clothes, shaking with shock and grief and terror. Because that first night, I broke down and told them everything that had happened. From the footsteps in the night, to the deep, seeping sense of evil I felt when I opened the attic door and stepped inside.

That, more than anything that came after, was the moment the key turned in the lock.

That was when they knew.

* * *

I’ve had a lot of time to think in here, Mr. Wrexham. A lot of time to think, and ponder, and figure things out since I started this letter to you. I told the police the truth, and the truth undid me. I know what they saw—a crazed woman, with a backstory more full of holes than a bullet-pocked signpost. They saw a woman with a motive. A woman so estranged from her family that she had come to their house under false pretenses, to enact some terrible, unhinged vengeance.

I know what I think happened. I have had a long time to put pieces together—the open window, the footsteps in the attic, the father who loved his daughter so much that it killed her, and the father who walked away from his children again and again and again.

And most of all, two pieces I never connected right up until the very end—the phone, and Maddie’s white, pleading little face, that very first day as I drove away, and her whispered, anguished the ghosts wouldn’t like it. And those two things were what did it for me with the police. My fingerprints on the phone, and my account of what Maddie had said to me, and the domino of effects her words began.