Tom and I grab a compartment together on the Hogwarts express. It's bitterly cold outside, and snow submerges the little station, so that it looks like an idyllic painting on a Christmas card. I cast a small heating charm in an attempt to dispel the chill, then fish two bottles of butterbeer out of my trunk.

"How is it that you always have alcohol to hand?" Tom asks, with a touch of amusement. He takes a bottle, and clinks it against mine.

"Butterbeer is hardly alcoholic," I say defensively. "And besides, the wizarding world is incredibly lax about little things like underage drinking. There are surprisingly few laws surrounding the purchase of alcohol."

"Well," Tom says, taking a large gulp, "the wizarding world clearly has no logic. I mean, think about it. They let you, an irresponsible teenager, purchase alcoholic beverages, and then complain when you smash things when you're off your face."

I blush furiously. "First of all, I was not off my face. Secondly, that was one incident, and I think it was completely justified."

"So the magical Scrabble board deserved it?" Tom asks drily.

"It said epiphinot wasn't a real word! Which it definitely is!"

"It's not a word," Tom says.

"Well, it should be," I reply sourly.

"It's a made-up word," Tom says.

"So were half of the words Shakespeare used! I think it's unfair for the Scrabble board to punish me for my undiluted creative genius."

Tom laughs. "You're insane."

I give him a kick in the shin, but can't help laughing too. "You know, that's not actually the first time I've heard that."

"I can easily believe it," he replies.

After arriving back at King's Cross, Tom takes my arm and we apparate to my house. Or rather, to just outside the front gate; no-one, including me, can apparate straight inside. It's one of the many precautions I've taken in order to keep it completely secure.

The house is Georgian in style: red-bricked and square, with towering chimneys and rows of lace-curtained windows. It's sizeable, but not excessively large, and squats in a little, walled plot of land surrounded only by the woods and, beyond that, the rolling Cambridgeshire countryside. Ivy claws at the walls, and almost smothers the porch, its leaves dusted by the sparse crystals of frost.

I open the creaking wrought iron gate, and gesture for Tom to enter. He does, and I lead him along the path and up the steps to the porch. All the while, he gazes up at the house like an enthralled child, his blue eyes wide. I suppose it must make a nice change from the orphanage.

The door opens automatically upon sensing my arrival, and Tom's look of wonder only increases as we proceed into a large, red-carpeted entrance hall, bedecked with chandeliers and two, great, sweeping staircases

"It's bigger on the inside," he murmurs in awe.

I refrain from mocking him for stating the obvious, instead smiling a bit as I place my suitcase down on the floor.

"The house's interior is infinitely large," I say, gesturing to the high ceiling and the sprawling staircases. "And it has a mind of its own. It likes to grow or shrink whenever it feels like it. Last time I was here, it had added a whole spa complex, complete with a sauna and everything."

"How?" Tom asks.

"A lot of magic," I say evasively. "Do you want to go and put your things in your room?"

"Sure," he replies, his pale fingers clenching around the handle of his trunk. "Where is my room?"

I shrug, grinning a bit. "Who knows? Just start walking, and you'll find it."

Tom stares at me for a moment in disbelief, as if wondering if I'm joking. "What?"

"That's how the magic of this place works," I say cheerfully. "Your every wish is its command. It'll know you're here, so I assume it's prepared a room for you. Just walk in any direction, and the house will rearrange to ensure you find it."

"Any direction?" he asks.

"Yes," I say impatiently. "Now go!"

He begins to walk uncertainly across the hall and up one of the staircases, glancing back every so often. I give him an encouraging smile, then turn on my heel and head to my own room. I have no idea where it'll be this time, so I likewise walk randomly, bypassing the stairs and instead taking a door on the left. It leads through the drawing room, then down a small flight of stairs to a long, blue-carpeted corridor framed with intermittent white doors. I walk past three doors until I feel the irrational urge to stop. I pivot, and the familiar door to my bedroom is before me, creamy white wood with a silver, serpentine door handle. On an impulse, I glance at the name embossed in brassy, golden letters on the door just across the corridor: 'Tom' it reads. Presumably he's already arrived.

"Open," I say in Parseltongue. The door handle twitches to the side and the door clicks open softly. I step inside my room.

There is planning to be done. I don't have long left, and I need to get what I came to Tom for.

I draw up a list at my desk.

Number one on my agenda is to get Tom to kill Hepzibah Smith. I'm not entirely sure if she needs to die, but it's better to be safe than sorry. Of course, in order for that to happen, I need to get Tom to infiltrate her house in some way. I already have ideas formulating on how I can make it happen. Oh, and the owners of Borgin and Burke's may also need to be dispatched.

Number two is to get Tom to take back what's mine. Not just steal it, but claim it, own it. There is powerful magic at play here, and the tiniest mistake could destroy me. My sole link to life must be restored to my bloodline before I can take another body, or else I risk death. Real death.

Number three involves me taking a little trip. Assuming that all goes to plan, I need to return to my cave in the mountains to ensure that the rebirth process is properly restored. Immortality is a delicate art; I cannot afford to cut corners.

My real issue in all of this is convincing Tom to partake in the scheme. I can't simply put him under the Imperius curse, or any other form of mind control. He must do it all of his own free will, or else the magic might fail. And what reason might I give for wanting him to do it? I could invent something, of course, but yet again the crippling fear of any kind of deception affecting the tenuous spellwork of my immortality cancels that as an option.

I have to tell Tom who I am, I realise. Have to, if I want to be absolutely sure of succeeding. That way he will do as I require, and there will be no lies between us.

What it comes down to, I suppose, is morality and immortality.