In far too short a time, Harry began to drop in altitude. I was amazed at how fast the city sprang up to meet us. For a few moments, as I began to pick out individual persons on the ground, I wondered if he could still slow down and pull out of the dive without slamming us to pieces. But I need not have worried. He knew what he was about, and though we seemed to swoop perilously close to the ground, he brought us safely to a level course over the rooftops.

The illusion which protected the Black house worked from above as well as from in front. But Harry found it, and landed on the roof. We climbed in through an upstairs window and took everyone by surprise by coming down the staircase, windblown and jubilant, somewhat earlier than they had expected us.

Mary and Shirley were there with Hermione, Sherlock, and the three Weasley boys. When I realized that we would be unable to return to Queen Anne Street until the end of the gang-war, I had intended to send them to Baker Street, feeling sure that the landlady, Mrs. Hudson, who was fond of Mary and doted on little Shirley, would be glad to let them stay in my old room for a short time. But Mary had been too quick to accept Harry's offer of hospitality. Harry seemed to think that he had a duty by her, whether because she was the wife of a team member, or due to the fact that it was, in a round-about fashion, his acceptance of my help which had led to her getting into trouble. The current theory under which muggle-born wizards were being persecuted was that they were actually muggles who had somehow 'stolen' magical ability, and were therefore thieves and usurpers (never mind that they didn't have any explanation whatsoever of how these villainous muggles went about this 'stealing' of a genetic trait). Harry thought, from Runcorn's words, that they had picked Mary out as being an example of a muggle who had attempted this theft. He was sure that Ministry officials would be after her in force and thought his own refuge the safest place for her to hide.

I was not entirely pleased with Shirley being here. Mary and I might take this place in stride, and Sherlock Holmes might laugh at the notion of anything about it being remotely frightening, but Shirley was a very little girl yet. So I was pleased to see that she was all right with it. She had really taken to the Weasley twins. They seemed to have put everything in just the right light for her; she was looking at the matter as quite the adventure without being actually frightened.

Sherlock and Harry were all for immediately setting about the council, and we only took a few moments before leaving Mary, Shirley, and the twins upstairs and headed down for the kitchen. The instant we had all taken our seats around the old oak table, Sherlock began talking.

"The possibility of needing to actually seize control of an area with arms had occurred to me some time before our collaboration began. This is far from unheard of in the world of police-work. The pretensions of this particular gang are admittedly higher than that of the ordinary criminal organization, but the fact remains that they are still a gang ... which has at this point seized control of a number of civilian institutions. Now, I asked my brother to have available a strike-team which could be called in – a special police unit with air-support. ... Now, if I am not incorrect in my approximation of the bank's security, it would technically be possible for us to get into the Lestrange's vault if we were able to fully convince the bank that we were the Lestranges..."

"I have some polyjuice potion!" exclaimed Hermione, interrupting Sherlock.

"What's that?" I asked.

"It turns you into someone else for a couple of hours." she explained matter-of-factly.

Since I was by now fairly accustomed to hearing shocking claims of that sort, and since my own ridiculous transformation of earlier in the day was still very fresh in my consciousness, I just nodded complacently.

"That line of action theoretically might work." said Sherlock, who seemed to know quite well what polyjuice potion was. "But it poses certain practical problems at the moment. We have no source of DNA from either of the Lestranges, nor are we likely to get any within the sort of time-frame I should like to accomplish this in. Moreover, there are numerous protections in place which, from the explanation of them that I was given, would stand a good chance of revealing the deception. Even if we got in, getting out might be problematical. Besides which, will they not ask for some further form of identification? George was required to hand over a key."

"But you just said that the thing to do was to convince them that we were the Lestranges." said Ron.

"No. I said that if we were able to do so successfully, that method would work. It is not the method I would recommend, and I believe I have just explained why."

"What method do you recommend?" asked Harry. "It sounds like you want to try to get the muggle strike team in. But it can't be as simple as that, because you must know that they couldn't do it."

"Not by themselves, no." said Sherlock with a smile, and I thought he was enjoying scandalizing the Wizarding teens. "I quite realize that this strike team on its own, however skilled and well-equipped, would be greatly at a disadvantage in a Wizarding establishment merely due to their ignorance of the technology. Hence the need to bring a team of wizards with whom they could work in conjunction."

For a minute there was silence. Then Hermione tentatively said:

"You mean combining a team of muggle policemen and the Order of the Phoenix?"

I had never heard the full name of the mysterious 'Order' before. I don't think Sherlock had either, but he gave no sign that the name was new to him.

"That is precisely what I mean, Hermione."

"Oh, come on, that's mental." said Ron. "We can't get a mixed army of muggles and wizards to take over the bank."

"Why not?"

"Well, for starters there's just the working together. How does that work? And then there's the actually breaking in. There'll be Death Eaters around for sure. And anyway, once we've taken the bank ... well, it'll be obvious something is going on and I reckon You-know-who will try to do something about it ... He might even realize what we've taken the bank for!"

"Excellent, Ron!" exclaimed Sherlock. "Yes, it is quite possible that he will. I am expecting it. In fact, I am counting on it."

"WHAT!?" exclaimed all three children at once.

"Well really, my good young wizards, there's no need to get so upset. And it is completely unnecessary for you to finger your wand beneath your robes, Ron. The only weapons I'm carrying at the moment are that wand and my riding crop, the one of which I cannot use, and the other of which is neither lethal nor ranged. My pistol is in my coat pocket on the back of the rocker and you know quite well you would not need your weapon whether I had it or no. If I wished to give your plans to Riddle I assure you that I could have done so without so much trouble, and I would hardlytell you that I was going to."

"Yes, we know that." said Harry, sounding a bit irritated and embarrassed. "No offence. But whatcan you mean by that?"

Sherlock leaned forward in his eagerness. "Don't you see that if we do find the cup at the bank there will be only two left?"

"We'll still have to destroy them all."

"Yes. But where is the only other inanimate one?"

"At Hogwarts. Well we think it is anyway..."

"Almost certainly it is at Hogwarts. And what is also at Hogwarts? ... Oh, come on, Harry. What else is at Hogwarts?"

"A lotta' security." supplied Ron.

Sherlock sighed. "And what else?"

"The sword of Gryffindor." said Harry.

"I thought we were certain that wasn't a horcrux." said Sherlock

"Yeah. Of course it's not. Just, Dumbledore left it to me in his will."

Sherlock sat up straighter. "Really?"

"Yeah."

"Why? It wouldn't belong to him, would it? And why would he want you to have it?"

"I don't know. I didn't find out about it until after he died."

"Say, Sherlock, do you mean the..."

"Hsh." Sherlock cut Ron off with a sound and a gesture without looking away from Harry. "Tell me about the sword of Gryffindor."

"Well, it was Godric Gryffindor's sword."

"Yes, that much I gathered."

Harry sighed thoughtfully. "I don't know much about its history, if that's what you mean, except for the fact that its very old. ... It's goblin made. I don't know why he wanted me to have it."

"I assume you do not have it because he did not in fact have a legal right to give it to you. Do I assume correctly?"

"Yes. The Ministry went over the will first, and they wouldn't let me have it."

"If it is a historical artefact, then it is likely publicly owned and so of course they would not. Dumbledore must have been aware of the fact. He must then have had some intention in putting it in his will other than that of transferring actual ownership of it to you ..."

"Sherlock, do you mean the basilisk?" Ron interrupted.

"Yes. I meant the basilisk. Thank-you, Ron. Which means that at Hogwarts – supposing that we are correct in believing one horcrux to be in Gringotts and the other to be in Hogwarts, and supposing we don't do something stupid and get caught – we can ..."

"Destroy the horcruxes." said Harry breathlessly.

"Precisely. So, we occupy the bank, we take the horcrux and we go straight to Hogwarts."

"Please tell me you don't want to take Hogwarts too." said Ron.

"No, I want to infiltrate it. Taking it would be highly counter-productive. I gather you three have had plenty of practice sneaking about the place."

The three looked at each other. Ron's and Harry's looks were sheepishly guilty. Hermione's on the other was highly dignified and a trifle reproving, as she had always behaved with the most perfect propriety. I knew for a fact that this was not entirely and completely true, if sneaking around the school counted as proper, since I had heard of a number of occasions when she had thought it the sensible thing to do just that. Doubtless she was thinking of some technically illegal escapades out of the grounds which I had heard that Harry had been known to do.

"I presume that you could get in if you tried hard enough?" said Sherlock after a moment.

"Yeah." said Harry. "Probably."

"And how would it be best to go about it?"

"Probably the Honeyduke passage. There's a secret trapdoor in the basement of the sweetshop in the village of Hogsmeade. It leads right into the third floor corridor in Hogwarts."

"Just how secret is it?" I asked.

"Very secret." said Harry. "I have no idea who made it. But we know about it. Fred and George know about it. My dad and some of his friends knew about it and ... oh. Wormtail must know about it."

"Pettigrew? The man who betrayed your parents?" asked Sherlock.

"Yeah. Him."

"Because your father knew about it and therefore so close a friend would also?"

"Well," said Harry, fumbling with a funny brown pouch, "because it's on the map they made together." And he pulled out a yellowed, stained, and beat-up roll of paper, which he spread out on the table. It was blank.

"Written in some kind of invisible ink?" I asked.

Harry smiled, grinned really, and almost winked. He took out his wand and tapped the paper.

"I solemnly swear I am up to no good."

Instantly, things began appearing on it, swirly swoopy lines at first, that looped playfully around the ragged page as if solely for the fun of it. But after a moment, they started forming into words.

'Messrs Mooney, Wormtail, Padfoot, and Prongs,

Purveyors of Magical Aids to Mischief Makers

Are Proud to Present

The Marauder's Map.

A complicated diagram of a very large building had appeared below the words.

"Wormtail. Well there's Pettigrew." said Sherlock. "I presume Padfoot is your godfather?"

Harry nodded.

Sherlock glanced over at me.

"His godfather was a shape-shifter – turned into a large black dog."

"Did he really?" I asked.

"Mm hm." said Sherlock. "And, considering this afternoon, you shouldn't find that too terribly difficult to believe." He was smirking immoderately.

"And uh, Mooney and Prongs," I said "– your father and a third friend?"

"Yeah. My dad's Prongs."

Sherlock leaned forward with a start of surprise.

"Is this working in live time?!"

"In what?" asked Ron.

"Is it current? Are these representative figures purely decorative, or are they showing what'sactually happening right now?"

I stared more closely at the paper, and immediately saw what he meant. The map was filled with small labelled dots – the labels read things like 'Minerva McGonagall' and 'Alecto Carrow'. And they were moving around.

"That's what's really happening." said Harry.

Sherlock seemed utterly absorbed in the map. He dropped into a chair, rested his head in his hands, and proceeded to pore over it as though he wished to memorize the whole thing.

Harry scowled suddenly.

"What's wrong?" I asked.

"Death Eaters in Hogwarts." he said.

"Oh." I said. "Are these all Death Eaters?"

"No. There's Professor Flitwick, there. He's the Charms teacher. I suppose they'll let most of the teachers stay as long as they don't openly oppose the new government. ... But there's Amycus Carrow." A hoarse tone had come over Harry's voice. "He was there when Dumbledore was murdered. ... And there's...." Harry broke off. A stifled cry rose in his throat. He snatched the map up from the table and thrust it furiously at Ron and Hermione, his voice torn with bitter sarcasm. "And we have a new headmaster! Of course! Wonderful choice! Why didn't I see that coming?"

"Why indeed?" mused Sherlock quietly. But his comment was lost in the wrathful oaths of the children – they had some very creative swearwords – even Hermione.

"What? What is it?" I asked in some alarm.

"Severus Snape is in the headmaster's study." said Sherlock matter-of-factly. "He was of course the obvious choice for the post. He has been a teacher at Hogwarts for many years – the only teacher who Riddle has any reason to repose confidence in. He has a foot in both camps ..."

"And he murdered Dumbledore!" cried Harry.

"From Riddle's point of view, that's hardly an argument against his appointment."said Sherlock. "On the contrary, considering that he finally made so clean and distinct a break from the Order he is the clear ... Well anyway. Even if the Death Eaters know about these passages through Pettigrew and plan on sealing them up, it's only been a few days since they've had control of the school. The school year won't start for several weeks yet. There's a very good chance they'll still be open. I see a number of passages marked here, so surely at least one of them should be. And, considering it's the summer holiday, there should be significantly fewer people and less security than there will be in a few weeks. We'll need to get to the shape-shifting room and the underground chamber; and if we do that we'll be able to destroy the locket, the cup and the diadem. Meanwhile, back to my assertion that I want Riddle to realize that we are after horcruxes – if he realizes this, is he not likely to be afraid that we may have already destroyed some? Will he not want to check and make sure that they are all where he left them?"

"Oh I do see!" exclaimed Hermione in excitement. "When he comes to check on the one from Hogwarts – probably alone, since he won't want any of his Death Eaters to know about it – we'll be there waiting for him."

"Exactly."

"The snake..."

"I think it highly likely that she will be with him. Fortunately, it is likely to be a highly emotional experience for Riddle, and so there is a great probability we will be alerted to whether or not she will be there and can decide whether we should retreat and find her, or wait in ambush for them both."

"That might really work." said Hermione. "So long as we beat him to Hogwarts."

"Oh there should be no difficulty about that." said Sherlock. "There will be a block of time before he finds out what has happened. Then we do not know in what order he will check the others, or whether he will do so immediately or not. We may possibly be waiting for him for some time."

"So, with this plan, we'd be having the muggle team attack the bank along with the Order of the Phoenix, and then leave?" said Harry hesitantly.

"No. I would have them remain on standby." said Sherlock. "They may be needed."

"How?"

"It depends on how both we and Riddle handle the confrontation at Hogwarts. He may bring Death Eaters with him ... or have them follow behind him. He may summon them when he realizes what has happened. It would be well to have a force on hand, to call if the need arises. And also, if Riddle were to believe that all his horcruxes were destroyed, all of them, and he was vulnerable as you or I to death ... might he not be quite compliant when faced with both the entire Order of the Phoenix and a pair of armed helicopters?"

Harry shifted in his seat.

"Well, I suppose that bringing capturing Riddle alive might be kind of an ideal situation, if it succeeded. It would – on the very, very off chance that it worked – allow us to bring him to trial."

"I am always in favour of bringing criminals to trial when possible." agreed Sherlock.

"When possible, of course. But, Mr. Holmes..." Harry paused for a moment, "why don't you justtell us why you so badly don't want to kill Riddle."

Sherlock stopped. He looked around at the three teenagers eager, confused, and slightly frustrated countenances. He seemed to be weighing something in his mind, or preparing himself for something. 'Now' I thought, 'now, he's finally going to tell us what is wrong'.

But it was Hermione who spoke next.

"It's always well to have a back-up plan!" she cried. "I don't think that that is a very good one. But the more possible options we have, the better!"

"Yeah, but the muggles won't be able to see to get into Diagon Alley or Hogwarts." said Ron. "How can they fly something when they can't see the place they're aiming for. And electric things don't work in Hogwarts – right Hermione?"

As Sherlock launched into how he intended to overcome these difficulties, Harry and I accidentally caught each other's eyes, and sighed together in mutual irritation at our friends' interruption. So Harry also knew that Sherlock was keeping a secret.

Sherlock still was explaining how the navigational difficulty could be very easily overcome by having wizards co-pilot, and why the aircraft would not actually have to enter the Hogwarts grounds to potentially be of great use, when there was the sound of a slamming door and raised voices.