"Until I was of age, I knew I was fairly safe – but I dreaded turning seventeen. It got more difficult, as time went by, but if any of my father's friends pushed me to declare my allegiance to the Dark Lord, I insisted that I needed first to complete my education to be worthy of serving him. The summer before seventh year, when the Ministry fell, I thought it best to leave the country. I toured the wizarding regions of Europe, keeping a low profile, using a false name. I didn't want to take the chance that they'd recruit me. I knew if they came for me it would be almost impossible not to join."

"Why didn't you stay abroad?" I ask. "You could have made yourself Untraceable."

"And abandon any hope of coming back, if Voldemort prevailed?" Nott snaps back.

"Surely a life in exile would have been better than living in Voldemort's Britain? You'd already had a taste of what it could be like. Don't tell me you could get used to that kind of violence."

Nott shifts uncomfortably. "I thought I might have to. I thought that maybe I would grow out of my squeamishness. It was bad, but I didn't know what else to do. Coming back to Hogwarts in the seventh year was like a sick parody of our old school days. You weren't there, you have no idea how awful it was. I would have left, but that was now illegal and the last thing I wanted to do was to draw attention to myself, to get the Snatchers on my case."

"So you fought against the better part of yourself and let evil take hold."

"You would put it like that," says Nott. "I was struggling with my sense of duty, and trying to make the best of things – that's how it seemed to me."

"After Cedric died, Professor Dumbledore made a speech about choosing between what's right and what's easy, do you remember?"

"I do. But I didn't apply it to myself as there didn't really seem to be any easy options."

"Just the path of least resistance," I say.

Nott grimaces. "My father knew what I'd seen had upset me. That in itself was disappointing; emotion has no place where blood and duty are concerned. We are brought up to be self-contained."

"Your father taught you Occlumency?"

"It's more that I was brought up in it. Even when I was a child, emotional outbursts were not tolerated. I was expected to suppress everything, because even if I didn't scream or cry, the pitch of strong emotions would cut right through the atmosphere, and my father would be furious. It was only later that I realized that everything my governess had taught me about keeping myself to myself was pretty much a form of Occlumency. But despite my efforts to conceal my feelings, my father knew that I hadn't made the leap from the theoretical to the practical at all successfully. Although I understood, I thought, the need for wizards to exert their authority, however brutal, over Muggles, I wasn't prepared for the reality of what that would mean..."

He shivers, and continues. "It's not the larger fact of murder that haunts you; it's the details…blood…and sinew. I know what it looks like when skin, muscles and veins are ripped slowly away from living bones. I wish I didn't! I wish I could forget…no, more than that, I want to erase every part of what happened from my mind. You would know better than most the methods one can use to keep thoughts from those who would try to access them, but there's nothing you can do to create such a barrier in your own mind. When you use Occlumency it's almost as though you underscore the memories you wish to keep secret; they stand between you and other people.

"I somehow thought that if someone looked me in the eye, they'd see what had happened that night. For the longest time, I was terrified of being exposed. But then I started being careless… I was still frightened, but I think at some level I just needed to connect with someone, however briefly, whatever the consequences. I couldn't keep avoiding people. But then I realized that I could look people in the eyes, hold their gaze so that they really saw me, and know that they still had no idea… that was the worst day of my life, the day I realized that I might forever be alone with what I'd done…"

"But you're here now," I say. "You've done the right thing in telling me."

He doesn't say anything.

"Whatever happens next, you're not alone with it any more. That has to be worth something."

He takes a deep shuddering breath. "I hope so."