December swept into Britain, bringing with it a whole series of new and exciting experiences for Harry Potter. He'd spent much of the previous couple of months marvelling at the slow changes in the colours of the leaves, the way the Thames was growing darker and more chilled-steel-like in hue, and how the air just looked a little duller, as the sun began to set earlier and the evenings started to draw in.

And within all these interesting changes to the world around him, Harry was most astonished by one ever-curious factor - the weather.

For down in Annwn, where Harry had spent the last decade, the environment rarely changed. Giant boilers heated the city, air conditioning regulated the atmosphere, and everything that could be controlled and monitored simply was.

So the first time that Harry Potter was rained on was quite a startling experience.

Now, he was expecting it to be wet - after all, he wasn't totally thick - but he wasn't prepared for how cold it turned out to be. Little icy bullets hitting his exposed head and neck every couple of seconds was quite the shocking thing. It didn't help that there were hailstones mixed in with the raindrops, or that it was a flash shower and that he didn't have a hood or an umbrella to save him from the assault.

That wasn't a mistake he was keen to make again in a hurry.

So that night, he huddled up in front of the fire with Minerva, who had made them both a mug of steaming hot chocolate, prepared a platter of custard creams, chocolate fingers and Scottish Shortbread biscuits, then prepared to teach Harry how to play chess, while he dried off and watched the steam rise from his sodden trainers.

Only this wasn't normal chess … for the pieces could move. Harry had seen similar things on Fizzizk Alley and had being dying to play Wizard's Chess ever since. But the experience wasn't exactly what Harry had been expecting.

For a start, the horse of the knight that Harry wanted to move actually bit him when his fingers got too close, which made Harry more than a little cross.

"Ouch!" Harry yelped. "Aunt Minerva … my knight just tried to eat me!"

Minerva grinned at him over the rim of her spectacles. "Well, it's a good job he wasn't this big then!"

And with that, she flicked her wand at the offending piece … which suddenly transformed into a version which was about five-feet-taller than the little piece Harry had been playing with. He rolled away to stop the powerful horse from trampling with his massive hoof.

"Wow!" Harry yelped in wonder. "Why did you do that, Auntie!? You nearly killed me!"

"Oh stop being such a drama queen, Harry!" Minerva chortled. "I am merely practising. This is my first year as Transfiguration Professor and I am out of habit when it comes to life-size transformations. The Headmaster has asked me to produce a full-sized chess set for a quirky game he is planning to play. Merlin only knows why. But that's Dumbledore for you. He always has been a funny sort of wizard."

"Why would anyone want a giant chess set?"

"Who knows?" Minerva replied. "But Dumbledore likes to play games. He probably wants to invite some friends to play, and they'd all take the place of a piece on the board. That would be quite interesting, actually. I'll have to build that instruction into the enchantment."

Minerva aimed her wand at the horse, whispered a spell, and the knight returned to his normal size again. Harry moved back to the board and sat cross-legged behind his pieces

"So, Aunt Min, how do I move the pieces, if I cant touch them? I don't want the Bishop to poke me with his staff, or something."

"You just tell them where to go," Minerva explained.

"And if they wont?" Harry asked.

"Then stop playing, because you're obviously a poor chess player!" Minerva quirked. "Wizard's Chess pieces are like horses - they know when you're not suited to playing with them and they'll bolt at the first sign of trouble!"

"Deserters!" Harry growled murderously at his pawns, who had all thrown down their arms and refused to move. "Can I have them shot for sedition?"

Sirius laughed deeply as he suddenly span out of the fireplace and emerged in front of them. He dusted himself down as he righted himself, ruffled Harry on the head, then moved to the mini bar he'd set up and poured himself a large whiskey.

"Wizard's Chess getting you down?" Sirius chuckled. "I never was much of a player myself. Well … at least not a chess player!"

"I don't think I am either," Harry agreed, sadly. "I'll just have to stick to being a pawn, rather than playing with one."

"What does that mean?" Sirius queried.

"Oh, nothing," Harry returned, brightly. "I was just thinking that I could help Auntie Min with her giant chess set. I think I'd be the right sort of size for your pawns, Aunt, if you want to use me as a template."

"Giant chess?" Sirius quirked, raising an eyebrow.

"Oh yes," Harry continued. "The Hogwarts Headmaster wants to play a game with giant pieces, so Auntie Min is making him one. It'd need a giant chess board to go with it, though. Where would you even keep something like that in a school?"

"Probably underground," Sirius mused. "There's as much space beneath Hogwarts as there is at surface level, after all."

"Ooh, really?" Harry began, excitedly.

But Minerva shot him down in an instant. "That's true … but if you even think about trying to explore the subterranean spaces when you attend the school I'll expel you myself!"

"Don't fret, kiddo," Sirius grinned over at Harry's crestfallen expression. "Minerva threatened to expel me and your old dad on a bi-weekly basis, but she never followed through with it. Blows more hot air than a set of bagpipes, this one!"

Minerva tutted and gave him a pitying sort of frown. She was still brushing soot from her robes. "You've never quite mastered the art of Floo Travelling, have you."

Just then, Harry started to guffaw quietly behind his hand. Minerva quirked a look at him.

"Did I say something amusing?"

"Yeah," Harry giggled. "You said foo … you know … like a girl's private bits!"

"What I actually said was floo," Minerva corrected with a grimace. "My accent may be quite thick, but your sense of humour is just as difficult to understand!"

"He's ten, Minnie Muck Gee," Sirius smirked at her. "Give the kid a break."

"l'll give you a break - preferably an arm or a leg - if you call me … whatever it was you just called me ever again!"

"You never minded it when we called you that when we were at school," Sirius reminded her.

"That's only because I never heard it," Minerva replied silkily. "Either that or you'd just forgotten to attend my class again."

"I'll have you know I was perfectly punctual," Sirius argued in mock hurt.

"Yes, but only to your dates, with whichever poor witch you were torturing with your attentions at the time," Minerva quipped back.

"You make me sound like a serial womaniser!" Sirius barked out in a laugh.

"I am suggesting nothing," Minerva fired over. "Simply pointing out that the school nurse had to give out so many salves to remove love bites that we thought we had a plague sweeping through Hogwarts. Either that or an outbreak of vampirism."

Harry giggled at that as Sirius simply shook his head in faux disgust at the slur. Then he opened the fridge. "What are these bottles? Where is my pinot grigio?"

"In the wine rack with a Chilling Charm placed on them," Minerva replied. "I'm storing some bottles of nettle wine for Severus in the fridge, part of a control measure for an experiment he's designing for Dumbledore. Try not to drink them too, will you?"

"Nettle wine as a control … for what?" Sirius asked.

"He didn't say. Where have you been, anyway?" Minerva demanded, changing the subject firmly.

"Hogwarts," Sirius explained, folding down into a recliner near the fire and kicking off his silver buckled boots. "It's a Hogsmeade Weekend, isn't it? Albus thought it might be easier to deliver his little vanity mirror while half the students are up in the village."

Minerva rebuked him with a stern glance. "The Mirror of Erised is no vanity mirror, Sirius."

"Then what would you call it?" Sirius queried. "What did it show you?"

"Oh, no, you don't get that sort of jump on me, Black!"

"Oh come on, Min!" Sirius urged, leaning forwards with boyish enthusiasm. "I'll er, tell you mine if you tell me yours!"

"Do lines like that work on any witch for you?"

"More than you know, but a wizard never tells," Sirius laughed. "So, come on."

"Not on your life," Minerva frowned.

"What are you talking about?" Harry interjected, utterly bewildered. "What's this mirror?"

"Dumbledore's latest curiosity," Sirius replied, sipping at his single malt. "He has quite a collection of such things up at Hogwarts. I'm expecting an announcement any day now … Albus Dumbledore, revered Headmaster of Hogwarts School of Witchcraft and Wizardry, has retired after eighty years in education to open up the Magical World's version of Ripley's Believe It Or Not! It's called Albus' Little Shop of Horrors!"

Sirius then laughed at his own jokey comment for a full minute.

Harry turned to Minerva, hoping for a sensible answer to his question. "What is it, this Mirror of … what was it called?"

"Erised," Minerva repeated. "It is an enchanted Mirror that shows whoever looks into it their heart's desire. But it gives neither wisdom nor truth, merely visualises the thing that a person desires the most."

Harry thought this was pretty cool, but was now hotly curious to know what his Godfather had seen in the mirror. So he asked him.

"Me?" Sirius quirked. "It seems a little unfair, considering that Minerva wont share her vision, but I have no problem revealing my own. I saw myself, on a cloud made of money, surrounded by a gaggle of busty, leggy witches, who were wearing nothing more than a feather boa and a smile. Oddly enough, it was the same thing I saw in a club on Immore Alley once, when James and I celebrated graduating Hogwarts. Only, don't tell your mother I told you that, Harry. It was James who provided the money."

"So, that's why James had to live with Lily's parents for the first year!" Minerva cried. "I did wonder."

"Yeah, James' old man wasn't best pleased that he'd frittered away a Trust Fund for James' first born on a series of erotic dances. Sorry, kiddo, don't hold a grudge for too long. Just know that the dancers were worth every Knut!"

Sirius grinned at Harry, who couldn't decide whether to be cross or not. "So, why wont you say what you saw, Auntie Min?"

"Such things are best kept private, Harry, or at least to a limited audience," Minerva replied, narrowing her eyes at Sirius. "Such things can be manipulated into weapons to use against you, or drive you mad in search of ways to make them come true, or to understand where they came from in the first place. Men and women have wasted away in front of the Mirror. They become obsessed by what they see, wondering if it is real or even possible. They focus on the dream, and forget to live."

"What does Dumbledore even want it for?" Sirius asked. "You know how cryptic he's become lately. He doesn't tell me anything these days. Do you even know?"

"I really don't," Minerva confessed. "Did James say anything to you? He did store the mirror here for months, after all."

Harry felt his heart slam upwards and lodge in his throat. The mirror… that first night … he'd seen it! He pulled back the confusing memory … the ghost girl holding his hand? His heart's desire? What was that supposed to mean?

"Earth to Harry? Have we lost you to the moon?"

Sirius was chuckling again, but Minerva seemed more concerned.

"Harry? What is it? You've gone very pale. You look as if you've seen a ghost," she asked in her worry.

"No, at least, I don't think I have," Harry muttered lamely. "I don't know … maybe I did."

"You aren't making much sense, kid," Sirius learned over. He looked attentive now, too. "What is it?"

"It's this mirror you are on about," Harry began. "I … I think I saw it. That night we all first met here. I went to claim my bedroom and … it was in there."

"And did you look in it?" asked Minerva.

Harry nodded.

"And what did you see?" Sirius pressed.

"I … I," Harry stumbled, immediately understanding Minerva's reluctance to make her own confession about her mirror-vision. She was staring at Harry so firmly, though, that he knew his own silence was not an option. "I saw myself but … I wasn't alone."

"No?" Sirius queried. "Who were you with … or what?"

"There was a girl there with me," Harry began. "And she had all her clothes on, before you ask! But … and this is the odd thing … she was holding my hand. It was weird because I could almost feel her there next to me. I know you're going to say I must have imagined that part of it, but I swear to you I didn't. It was like she was right next to me, but at the same time a million miles away. In a different world, maybe, but one side-by-side with ours."

Something flitted over Sirius' expression a moment that wasn't concern or anxiety, but something else that Harry didn't understand at all. It might have been fondness, or regret, but neither of those things made any sense. In any case, the look was gone as quickly as it arrived, gone so fast in fact that it made Harry question whether he'd seen it at all.

"Can that be possible?" Harry ploughed on. "Could there have been another person there with me, one that wasn't just a reflection? Was it like that for either of you?"

The matching looks of puzzlement on the faces of the adults gave Harry his answer in about three seconds flat. This wasn't normal, clearly, and Harry shuddered with a surge of discomfort. Seeing, hearing - and especially sensing - things that other people couldn't was never a good sign … not in any world.

"It wasn't, was it? Please tell me," Harry mumbled meekly.

"No, it wasn't, kiddo," Sirius replied. "But maybe you're just hyper sensitive to things like this. Maybe there was a ghost with you at the same time, one who happened to stand in the same spot as the girl in the reflection. What did she look like anyway? Was she pretty?"

"I … I don't know," Harry blushed as his Godfather smirked teasingly at him. "I couldn't really see her face. But yes, I think she was pretty. I sort of knew that about her, even though I couldn't make her out very well. That sounds weird, doesn't it?"

"Not at all," Sirius quipped happily. "If a pretty girl wants to hold your hand, that's something to be smug about. I should know!"

"Even if she's a ghost?"

"Especially if she's a ghost!" Sirius boomed. "Think of the benefits. You get all the companionship of a girlfriend, but you don't have to meet her parents, or buy her expensive presents, or take her on dates, and there's no chance she can tie you down by getting up the duff. That's why my favourite girlfriend was a ghost."

"You had a ghost girlfriend?" Harry quirked with a grin. "When?"

"I certainly did, back when I was at Hogwarts," Sirius revealed with a wide smile. "I was with her for five years … longest relationship I ever had. She used to haunt a girl's bathroom, not a fan of big long snakes … which would have been a serious barrier to our love, you know, had we been able to, er, get physical."

Sirius chuckled loudly to himself, while Minerva scowled at him in disgust.

"You really do have all the charm, wit and sophistication of a Dementor after a head-swap operation," Minerva sniped. Then she turned to Harry. "I wouldn't fret too much about this vision of yours. I imagine that it is just that side of you that yearns for companionship beginning to emerge. It seems perfectly understandable."

"It does?" Harry asked in hope.

"Of course," Minerva went on with certainty. "You, who have never know friendship with those of your age, can think of no greater fulfilment than the chance to put that right. And there will never be a friendship more fulfilling than a romantic relationship. You are very young, and at your time of life the idea of such things is abhorrent. But that will change, it always does as you get older. And romance is a beautiful and wonderful thing. If you take one lesson from me this year it will be that your Godfather's view of things is the most vain, vacuous, self-absorbed, arrogant -"

"Hey … you are listing all my best qualities there!" Sirius teased. "No, look here, Harry … Minerva is right. Romance is lovely, I should know - I've been in love with myself for years! And look how happy I am!"

Harry smiled weakly as Sirius burst into peels of laughter again. He shook his head and turned back to Minerva for some sense. "But does this mean that my heart simply desires romance … or that this girl I saw is the one that I'm going to have a romantic relationship with?"

"I would guess - based on that fact that you didn't see her face - that no, it wont refer to someone specific," Minerva mused. "I could be wrong, of course, but perhaps it just gave you an ideal, a template possibly, of the sort of girl you will be attracted to, when you start to feel such things"

"Well, she did have a lot of hair … and I mean a lot," Harry replied thoughtfully. "I've always liked thick hair. My Mum's gets very bouncy when she grows it out. I always liked smoothing it."

"There we go then!" Sirius barked in triumph. "Just be on the lookout for a girl with masses of bushy hair and try to work out if she's the One. Just try and make sure she has a bit of cash behind her before you fall in love … your Dad really did screw you over on that score when we were eighteen!"

Minerva shook her head in pity again and turned to Harry. "What do you say, after dinner, to helping me decorate the flat ready for Christmas?"

"Oh, yes please, can we!?" Harry cried, exuberantly. "Can we get a steamers?"

"Of course."

"And tinsel?"

"Yes."

"And a tree?"

"The biggest," Sirius chuckled. "We can even get pixies to live in it to be the lights."

"What … real life pixies?" Harry asked in awe.

"Yep, kiddo, real life ones," Sirius grinned. "You'll have to stop saying that soon. The Magical world isn't a fantasy any more … this is real life for you now. You have to stop trying to disbelieve everything new thing you come across."

"I hope I don't," Harry disagreed. "I love the surprises … I hope they never stop!"

"In that case, open the next window on your advent calendar," Minerva encouraged.

"Yeah, do that," Sirius nodded. "But be careful … you could just open a doorway to another world, and who knows who might come strolling through if you do. It might even be your mystery girl from the Mirror!"

"Is that … possible?" Harry asked cautiously, trying to fight his natural urge to question everything magical.

"Of course not," Minerva dismissed at once. "There are no such things as other worlds. Tell him, Sirius."

Sirius cleared his throat. "Er … no. Of course there aren't. I was just joking around. Go ahead and open the door, Harry … you're quite safe."

It was only later, much later, that Harry remembered noticing that Sirius didn't quite meet his eye when he told him that …