At these alarming sounds from upstairs, Harry snatched up his wand and flew from his chair. The rest of us followed; Sherlock making sure to run over and grab his pistol.

Up in the foyer, we found the twins standing upon the doormat with a lean, tired looking man in a dark cloak. As we came in, one of the twins cheerfully called out:

"It's okay, Harry. We've checked him."

The three rushed eagerly forward to greet the visitor who they evidently knew quite well. As he turned to meet them his eyes fell upon Sherlock and I, then flashed up to the landing above, where Mary must have been standing. For a moment he stared in shock.

"Harry," he said quietly, "Who are these people?"

"Ahhh ... they're sort of ... allies. Who have been helping us ... fight Voldemort." said Harry awkwardly. "Um, this is Mr. Sherlock Holmes and Dr. John Watson, that's Dr. Watson's wife Mary up there. She's here to hide from the Ministry officials who're after her ..." He turned to Sherlock and I. "This is Remus Lupin. He's a member of the Order and was a professor at Hogwarts for a while."

"Hello, Mr. Lupin." said Sherlock, at his most affable, extending a hand to the rather disturbed looking wizard. "I am sorry to see that you had such difficulty getting here. Did you manage to lose your pursuer, or were you forced to more extreme measures?

"Ah ... No, I managed to lose him." said Mr. Lupin, taking Sherlock's hand rather reluctantly, as if he wasn't sure how to avoid doing so.

"Wait, lose who?" asked Ron.

"I would have been here earlier, but I had to lose a Death Eater who was trailing me. ... Harry, can I talk with you a minute?"

"Yeah." said Harry, and followed him out of the room. For a minute the rest of us were all silent. Then the twins burst out laughing. They seemed to think the matter immensely entertaining.

Sherlock too seemed cheerful, and was chuckling to himself in his quiet way. I myself thought that this had complicated matters.

"Well, Mr. Lupin didn't look any too pleased to find out that Harry had been trusting Order secrets to strangers." I said. "Harry didn't seem too keen about your combined strike-team idea, and I suppose he'll harder to convince now."

Sherlock shook his head.

"No. I think precisely the opposite. Remus Lupin has shown up just in time. He isn't just displeased, he's angry. And he's already put Harry on the defensive. Harry will defend his own actions by defending their outcome. That is, by defending what has been accomplished. And by the time that he and Mr. Lupin have argued the matter out, Harry will have argued himself into stubborn agreement with me." Thus saying, he lit his pipe, stretched out his legs, and settled down to wait for Harry to argue himself into reason.

We were waiting for some time. Harry and Mr. Lupin talked and talked, and a couple of times we heard raised voices. Sherlock smoked silently. The twins played with Shirley, and chatted with Mary. But I became rather impatient. The delightfulness and busyness of the evening had not effaced the problem of Harry's wound from my mind. I wished to be doing something, and chafed under the inaction.

When the door finally opened and they came out, Harry was looking decidedly cheerful and confident. Lupin still looked wary, but no longer appalled. I saw now that he was a younger man than I had supposed at first; he could not be past his middle years yet. The prematurely greying hair and the haggard, tired face were deceptive. When he spoke, his voice was serious and it brooked no argument; but there was no hostility in his tone, merely caution.

"Mr. Holmes, I would like to talk with you for a minute." Lupin looked from Sherlock to me. "With both of you, actually."

"Of course." said Sherlock agreeably.

Lupin turned and walked out of the foyer. We followed. He did not take us to the little side room just off the foyer where he had argued with Harry, but into a room I had never gone, a long narrow room lined with cupboards. There, he turned around and faced us.

"You have told Harry that you can help him defeat Voldemort within ... a few days?"

Sherlock did not immediately answer Lupin; he stood there, his head bowed in thought.

"If he has said so, I shall not contradict him." he said finally. "I did not give a specific time estimate for the plan and that approximation is his, not mine. But it does seem to me to be a perfectly attainable time estimate, should the plan succeed at all. It isn't an infallible plan. We may succeed in doing nothing except eliciting further violence against muggles, which would of course be disastrous. But if it works, then yes, that estimate is quite reasonable."

"And you think it will work?"

"I think there is a very good chance it shall do so."

"Mr. Holmes, I'm sure you can see how this is a very delicate and important matter?"

"Of course."

"And you must also see how very necessary it is that we be sure we do not misplace trust."

"Extremely necessary. I quite agree."

"And if you are really telling the truth about this ..." Lupin stooped and drew a small brown bottle out of one of the cupboards.

There was a low intake of breath beside me and I turned to see Sherlock tighten his jaw. But momentary appearance of dismay was gone so quickly that I almost though it had been some trick of the dim light.

"... Then I presume you would not mind a test?" Lupin continued, holding up the bottle. "This is veritaserum, which renders the drinker incapable of not telling the truth. Harry has been trusting you for days. If things are as they seem, then he has made a good, if strange, decision. But as an adult wizard, an Order member, his ex-defence against the dark arts professor, and his friend, I would like to be a little more certain that things are as they seem."

"Very reasonable of you." said Sherlock, his brisk tone unaltered. "I applaud your caution."

"Will you drink it?"

"Under one condition."

"I'd rather not give conditions."

"Hear it before you refuse, my good fellow. It is merely that you don't ask me any question which Harry has refused to answer. A part of our initial agreement was that I would not reveal certain things to anyone – And I am afraid that includes even members of the Order of the Phoenix."

After a moment's thought, Lupin agreed to this.

"Then certainly I shall drink it." said Sherlock.

Lupin took the wand which he had been holding in his hand, and I saw something glimmering in the dimly lit corridor. A moment later I realized I was looking at flowing glass. Unlike in traditional glass-blowing, I couldn't see where the glass was coming from and the finished vessel was cool, solid enough for him to take it directly out of the air and hold it in his hand.

"Aguamenti." he said, and like a tiny hose nozzle, the tip of his wand shot out a narrow stream of water into the glass.

"Where does the water come from?" asked Sherlock. "And please don't say 'magic'."

"Okay." said Lupin, unstoppering the bottle. "I won't say that it's magic."

Sherlock sighed audibly.

A single drop of veritaserum wavered on the lip of the bottle, and dropped invisibly into the water. Lupin held it out to Sherlock and Sherlock unhesitatingly reached to take it.

"Hang on a minute." I said. "What is in there?"

"Water and veritaserum." said Lupin.

"Yes, but what is veritaserum? I mean, I'd like to know a little bit more before he drinks it."

"I can't tell you the ingredient list ... I'm no potioneer. But it's considered perfectly safe for human consumption. It renders the drinker incapable of lying or refusing to answer, and wears off after a while, depending of the strength of the dose. This is a light dose and should wear off in under a quarter of an hour."

"Side effects?"

"None that I know of, at least none lasting beyond the quarter hour."

"I'm sure it's fine, John." said Sherlock, and took the glass from Lupin.

He set the empty glass down very slowly on a dusty side table. He blinked. The dismay was unmistakable this time; there was a sudden jolt of fear in his eyes. He darted me a glance that was almost like a cry for help. But though I started forward I had no idea what he wanted me to do. Then he looked back to Lupin, remained standing straight, and gave no overt signs of being in trouble. But the business-like manner with which he had been conducting the matter was gone. And he wasn't dreamy either. He looked something like a sleepwalker. It was so unlike any manner I had ever seen him in, even when drugged, that it made me very uncomfortable.

"Okay," said Lupin, "who are you?"

"Sherlock Holmes, the consulting detective." he replied, quietly and unemphatically.

"You are a muggle?"

"Yes." said Sherlock in a flat drone. "Or at any rate, I can't make a wand do anything and I can't see the Leaky Cauldron. I have tried of course, just to be certain." There was a kind of rambling, undirected feel to his speech. I didn't like it.

"Who are you working for?"

"I'm self-employed. My clients hire me for individual cases. No one has specifically hired me in the Riddle case. I'm acting without a client, unless Harry Potter counts as one. Probably not. He's not paying me and our collaboration was my idea, not his. I had quite a job to convince him. Thank goodness for Hermione."

"Why were you so anxious that the collaboration should take place?"

"Because it was obvious that he knew a great deal more than I did about the matter and information was precisely what I needed."

"Needed to what?"

"To get rid of Thomas Marvolo Riddle. I've been trying to trace him for many months. But just trying to figure out a little bit about the Wizarding world was difficult enough. Clearly I needed to be working with someone who knew the Wizarding world. And Harry definitely needed to be working with someone who had a clue. So all around I thought it was a most excellent arrangement and it has worked pretty well thus far."

"Harry said you were alerted to our existence by the murder of Amelia Bones?"

"I was. Ordinary murderers don't teleport. It's been almost twelve months since I became aware of Riddle's existence and by extension that of the whole Wizarding underworld."

"And in all that time, you've never been caught?"

"I have been caught on several occasions. Seemingly by fairly decent wizarding citizens and officials, however, not by murderous thugs looking for kicks. I was investigating what seemed likely to be major public places of the Wizarding World in my attempt to get far enough into it to see what was going on with Riddle, and the Death Eaters were still outlaws at that point, so it is perhaps not extremely surprising that I didn't run into any."

"You were captured on several occasions, yet you somehow managed to escape obliviation every time?"

"I did not escape."

I looked at Sherlock in surprise and alarm. His voice was still toneless, and his eyes were strangely empty, but his face was contorted as if he was in pain.

"No, they took it," he said, "they stole from me, stole things that I knew, that were mine. Once I knew it. And now it's gone. Hermione didn't, she listened to me. But the others, all the others, they took it, took my mind – cut it, pasted it, forced it into what shape pleased them...."

Sherlock had not spoken of his memory-wipes since mentioning them so briefly the night we joined the trio; his manner then had flippant, almost jocular. But I realized now that I should have known better than to believe it.

"Well," said Lupin, faltering, he could not but realize Sherlock's distress, "... if you were obliviated, how is it your investigations continued?"

"They took away what was in my mind then. I don't know what I did. I can only imagine I managed to conceal from them how far back my knowledge went. I lost days. Hours. They're gone. I can't find them. But nobody stole or mutilated the start of my investigations, and so I was able to continue. I started writing where I was going and why before I left the flat. I sent myself email updates on my phone with a special code attached so I'd be sure it was me who sent them, and I took pictures and videos. I have notes and letters and photographs which I know I wrote and took, but the writing of which is gone forever. I lost a phone that way one time – and a longer period of time than the others. That wizard must have been more thorough than most. I expect he was, in spite of things, a decent enough fellow – the phone was gone with the days he stole, but he paid me handsomely for it. There was a significant sum in my wallet which I am certain had not been there before. I took a gamble on Hermione, a big gamble. I went all the way back and I staked everything on her ethics and reasonableness. I openly told her how far back my knowledge went, hoping that the very length of time would now be for her an actual barrier. My gamble paid off, better than I could have hoped. And thanks to her, the end of the case is in sight."

"The case?" asked Lupin.

"Yes, the case." droned Sherlock.

"Your goal in 'the case' is to get rid of Lord Voldemort as a criminal threat?"

"Yes. But who calls him 'Lord Voldemort'? I'm not about to humour him by using his silly anagram. He's no more a 'lord' than I am. And 'Lord Flight-from-Death' would sound moronic in any case."

"You are really trying to work with Harry?"

"Yes. As much as possible."

"What does that mean?"

"It means that he sometimes does stupid things and I don't go along if I think it's stupid."

"Who specifically are you working to benefit?"

"The whole British population of course."

"Does that mean muggles or wizards?"

"I wasn't differentiating."

"Have you revealed to anyone the secrets which Harry has revealed to you?"

"Yes. I have told divers details to my brother, now and again. Harry knows this, and he is annoyed at me, but it's for his own good. Mycroft can be very useful. John's wife followed he and I right into the thick of things, but I'd told her not to – twice. So that wasn't really my doing. And Harry knows all about that, he's offered to let her and little Shirley stay until the Watsons can return home. They can't right now since the Ministry of Magic has their address and have marked Mary as a poster-girl villain for their wand-thief propaganda. I was talking about the case to a friend of mine, last night at the lab, while Harry was asleep. But I was purposefully vague on the details and gave away no actual secrets. And she kindly didn't attempt to pry – she has discretion, and good sense, and completely understands my not infrequent need for secrecy. I haven't told any of the secrets from Dumbledore to anyone."

Lupin nodded; he was starting to look convinced. Sherlock was inexpressive.

"You really are just trying to help Harry with his mission and rid the Island of a terrible criminal then?"

"Yes."

"You have no sympathies with Voldemort?"

"None in the world. He's not even especially clever about his crimes; boring, obvious mad-scientist."

"Now, I know I agreed to not ask you to tell me everything ... but have you told Harry everything? Are you hiding anything from him?"

For the first time, there was almost a flicker of hesitation in Sherlock's unsettlingly blank eyes. But a word slipped out of his mouth nevertheless.

"Yes."

Lupin's calm face grew suddenly hard, and his reasonable voice took on a sharp edge as he demanded:

"Why?"

"It isn't necessary yet."

"What do you mean it 'isn't necessary'? You're going to hide some relevant information until you deem it 'necessary' that Harry actually know?"

"Yes."

"Why?"

This time I was certain that Sherlock answered totally against his will; it was difficult to catch the thickly muttered words.

"I'd rather he lived these last few days. I don't want to end it before it really has to be over. It'll do him no good to know now. I'll make sure he knows when he has to but he doesn't, not yet."

"How can he make the right choices if he doesn't have all the information?"

"He can make this choice last minute. That's part of why I need the Order. To allow him the margin of choice. But he's already made the choice, really. And he won't change. And he's right."

"What choice?"

"Look!" I interrupted, finally breaking down and trying to do something about the wordless panic which my friend seemed to be helplessly caught in. "Mr. Lupin, I believe that this is the secret problem which I've been trying to get him to tell me for days. He has refused to tell me on the grounds that it shouldn't be told yet. I've worked with him for many years and I have a good deal of respect for his judgement in such matters. He's probably right to wait. And in any case, I think you're crossing the bounds you agreed upon."

"No. I agreed not to ask him anything that Harry already refused to answer. If this is a secret that you won't tell Harry, it can hardly be a secret that Harry won't tell me. If Harry's in danger – danger beyond the obvious – I have to know what it is."

"I'm guessing that in order to tell you this, he'd have to also tell you what he's agreed not to say."

Lupin turned back to Sherlock, who was just standing there stupidly with a strained look on his immobile face.

"Does this relate directly to the secret mission?"

"Yes."

Lupin sighed and bit his lip. He stood there for a few moments, doubtless weighing all the things Sherlock had said before, and trying to see whether he could trust Sherlock on this point by what he'd said about other things. Before he could speak again, there was commotion from the foyer. Lupin immediately walked out of the room back towards the foyer. I followed.

"No! I'm fine, Fred. Leave me alone a minute!" Harry, wincing and stumbling, his hand clapped to his forehead, was trying to make his way out of the foyer, away from everyone.

"Harry! What's the matter?" asked Lupin, running forward.

"Nothing. Just, my scar hurts."

Lupin's face twisted, and I saw that this phenomenon was not new to him. Taking a deep breath and speaking in a voice of forced calm, he said:

"Yes, it's bound to hurt a lot now, Harry. Guys, leave him alone."

I didn't know if Harry had heard him, his eyes had scrinched shut and he'd crouched down to the ground with his head in his hands. I stepped towards him.

"Dr. Watson, stop. Leave him alone." said Lupin, laying his hand on my arm. "I know you're a healer. But there's nothing you can do for him right now."

"Nothing?" I asked. "How can there be nothing we can do for him?"

"There just isn't." said Lupin. "We don't really understand very well what's wrong with him either."

It seemed to me extraordinary and terrible that the young man should be in such distress and we, his friends, stand by and make no move to help him.

The floorboards creaked behind me and turned to see that Sherlock had followed us into the foyer. His eyes, though still somewhat clouded, were fixed on Harry. The vacancy was much less.

Harry looked up, breathing hard. He fixed Sherlock with a rather accusing expression.

"You've been having your brother arrest Death Eaters after all, haven't you?"

"Yes." said Sherlock. "I expected he would use the information I've been giving him to do so. And, no, I am not sorry."

"Well you shouldn't've." said Harry, starting to get to his feet. "I didn't turn down your offer because it wouldn't be playing fair but because it's too dangerous. Somebody named Yaxley has disappeared now and Riddle's furious. They'll get away, and the muggle guards will be hurt. Or worse, Riddle will figure out where they are being kept and lead a force to take them and then ... Sherlock? What's the matter? You look ..."

"It's just veritaserum, Harry." said Lupin. "It should be mostly worn off already."

"You used..."

"I didn't ask him about your mission."

Lupin turned around and addressed Sherlock in an undertone. I, who stood right next to them, heard what he said.

"Is it about that scar and the connection with Voldemort?"

Sherlock nodded.

"You're afraid it's going to put him at risk in Voldemort's destruction."

"Yes." said Sherlock quietly. "In some fashion or another."

Lupin sighed. "You could possibly be right, Mr. Holmes."

Sherlock looked from Harry to Lupin with a swiftness and purpose which assured me that he was coming back to himself.

"Is he? Do you know? Is there anything that can be done about it?"

"No I don't know. And I'm afraid that nothing can. I don't know what will happen to Harry when Voldemort is killed. ... Perhaps it will heal him, not hurt him."

Sherlock looked as though he was going to say something, but stopped, shaking his head.

Lupin turned to Harry and spoke in a normal voice. "All right, Harry. If you're sure you need to break into Gringotts, I'll take that message to Kingsley and try and convince the Order. If you're sure about it, they probably will. Things are going badly right now and any plan will be welcome. Is there any other information I should take with me?"

"I dunno. Sherlock? Did you have anything more specific that you wanted to show us?"

"Yes." said Sherlock. "About the strike-team and the bank. If you come back down to the kitchen we could discuss them in greater depth."

"What about us?!" cried George.

"Yeah, if Remus can join in, why not us?!" agreed Fred.

"I cannot imagine why not." said Sherlock. "Harry? I assume you will involve them in this operation anyway."

Harry of course welcomed them, and all the Weasleys, wizards, et cetera headed on downstairs. I accompanied Mary and Shirley back to the parlour, Shirley in my arms, for the halls were black and ugly and now Fred and George were not there to turn it into a jest. Mary followed me out into the corridor when I left.

"John, our young host, how did he get that wound upon his brow?"

I hesitated a moment, but Mary was now aware of the secrets of the Wizarding world, their hidden places and mystery tools, and this was not a tactical secret, revealed in confidence. It was common knowledge. So in a few, brief, inadequate words, I told her the story that all the Wizarding world knew, of how the murderer tracked down the young family, and slew the father of the household, and of how the young mother had cast herself in front of the cradle, and – somehow – cast upon her son a shield, and how the deadly blow had rebounded off the boy's brow and almost slain his attacker.

Mary heard this story in perfect seriousness, when it was done, she asked but one question.

"Does the shield remain?"

"No. I don't think so."

"Why not?"

"I don't know. ... We don't know how it worked in the first place."

Mary looked very thoughtful, but didn't respond, and retired back into the parlour.

As I was traversing the ground floor corridor, walking slowly, deep in thought, my feet making little noise on the ancient carpet, I was surprised to hear voices, not in the kitchen but in the downstairs corridor.

"Well, that certainly is one of the possible options." Sherlock was saying.

"Sherlock." said Harry, clearly frustrated. "Just, tell me plainly – do you really think anything else anything else is really and truly going to rid the world of Riddle?"

I hesitated on the top of the stairs. Sherlock's voice floated gloomily up to me.

"No. ... Most probably not."

"Then ... what's the point in messing about with these other ideas? I know that we probably won't all survive the encounter – I don't really see how we can. But if we can rid the world of him ... well ... we've got a duty, haven't we?"

"Yes. We do. I quite agree. ... Just so long as you are fully aware ..." Sherlock broke off.

"You really do agree with me then?" said Harry. "I mean, after all your ... whatever you call it, we actually are agreed?"

"Yes." said Sherlock. "Harry, we are so very agreed."

And in my mind's ear, I heard my friend's voice out of the past; the crisp, cold syllables as clear to my ears as if they had been spoken only yesterday.

"If I were assured of the former outcome, I would, in the interests of the public, cheerfully accept the latter."

The former was the destruction of Professor Moriarty, the criminal mastermind. The latter was Sherlock's own destruction. Years had passed since Sherlock had spoken those words. He had not had to pay so high a price for his victory. But, violently contrastive as Sherlock and Harry doubtless were, foolish and frustrating as Sherlock found Harry's methods and odd and outrageous as Harry found Sherlock's, in this they were alike, akin.

"Ah, you know, Sherlock," said Harry, "you and John don't really need to be there ... As in, that'd be kind of silly. I really appreciate all the help you've given us, and if you can get us to the point we've talked about, that'd be just great. But ..."

"Oh, don't be ridiculous, Harry." said Sherlock, switching into a flippant vein. "Anyway, you should just try to tell John Watson that he doesn't need to be present at the scene of action. Never works. ... Does it, John?"

I finished coming down the stairs. Harry looked up in surprise; he clearly had not heard me.

"Well, it hardly seems fair." he said. "Not to be rude, but, the two of you are muggles."

"And the three of you are children." countered Sherlock.

Harry was still protesting that seventeen-year-olds did not qualify as children when we got back to the kitchen.

It did not take Sherlock very long to go over the details about the proposed strike-team and explain the theorized plan of attack. Hermione 'magically' copied some of Sherlock's papers for Lupin to take back with him. Fred and George clamorously volunteered for the job of co-piloting the helicopters. But both Harry and Sherlock thought it best to leave specific arrangements of that sort to be decided by the head of the Order and the commander of the strike-team.

Mr. Lupin hurried off as soon as possible, promising to bring the plan to Kingsley Shacklebolt immediately and to get back to us on the matter by morning. Before he left, he warned Harry to expect more guests, as a great many more Order members would probably show up here before long.

The five teens were very merry. They bid Lupin goodbye with gusto; and after he left and they were tramping on up to the parlour, they were all laughing and jesting. The war might have been won. But as they turned up onto the landing, I saw Harry's hand stray again to his scarred forehead; another spasm of pain passing over his face.

"You see it? Don't you?" asked Sherlock quietly.

I turned sharply.

"No." But I wondered as I said it if I was really being honest.

"Harry is wrong. Riddle didn't make six safeguards."

I didn't say anything. I just waited for Sherlock to finish – hoping that I misunderstood him.

"No." said Sherlock. "He made seven. ... Harry Potter is the seventh safeguard."