The next hour was a flutter of activity, very little of which required John's presence. Sherlock busied himself at Dumbledore's desk for well over half an hour, writing on a roll of parchment with an enormous feathered quill as though he had been doing it all his life. Occasionally he paused to scratch something out or scribble a note in the margin. It was easy enough to figure out what he was doing. Spilling Voldemort's secrets.
Sherlock confirmed this when John asked him about it.
"Everything that's been locked in here," he pointed to his temple, "Dumbledore and the Ministry need to know, urgently. Needed to know fifteen years ago. Death Eaters are walking free, John. Dormant, probably. Why risk their necks without their master present? But they're among us, all the same…"
"Among you," said John. The words spilled out of him.
Sherlock looked up, brow creasing.
"Among you. I'm not a wizard. What happens after all this, Sherlock?"
John clamped his mouth shut, but the question had already escaped, the one that was making him physically ill. It was disconcerting enough to learn that an entire magical world existed behind one's back, far worse to find that one's best friend was darkly embroiled in it. Sherlock had his memories back, his whole world back. Where did John fit into that?
But it was unbelievably selfish to ask, when children were in danger.
"Never mind," John hastened to say, regretting his interruption of Sherlock's work. "It isn't…"
"It is important, John. It's the most important thing in the world to me."
The emotional candor was so unlike Sherlock that John squeezed his eyes shut, afraid to see his own anxiety mirrored in Sherlock's expression.
A hand grasped his own, tightly.
"I mean it, John. Life at 221B-"
"That's just it," John interrupted. "How can it possibly compare to this?"
"I'm a little old for high school, John."
"You know what I mean."
"I don't cease to be a wizard just because I live in central London. Nor does my calling change."
"Really?" It took a moment to process this. "You're trying to tell me you aren't a...magical chemist or something?"
"Well, everyone needs hobbies," Sherlock said. "The term is 'potioneer'. But as to the sense of your question, no. My only occupation in the Wizarding World is Death Eater, and apparently turncoat. To be frank, I prefer 'consulting detective'."
John took a breath. "How are we going to keep this from Lestrade?"
"More easily than you think. I have all manner of illusions at my disposal now."
"Like you didn't already."
"John, we'll make it work. I promise."
The vow shook John from his paranoia; he had never heard one from Sherlock before. A moment later, however, his fist clenched.
"What about the other Dead-"
"Death Eaters."
"Yes. What if they come after you?"
Sherlock snorted. "John, when is the last time I didn't have an assassin or two after me?"
"This is different."
"Fine. But you're forgetting they all think me dead."
"You don't think they'll figure it out?"
"Frankly, no," said Sherlock. "Don't forget we're at a school, John - the finest the Wizarding World has to offer, if you'll forgive the jingoism. The people you have met here are intellectuals. They're about as close in intellect to the general Wizarding public as you are to Anderson."
John blinked. "Was that a compliment?"
"Possibly to Anderson. The point is, John, that what you are postulating is incredibly unlikely. I was a teenager when I disappeared, at a time when dozens of people on each side were vanishing. Most of them dead, some captured."
"But the others are in this...this prison?"
"Azkaban. Yes."
"They know you aren't there."
"Even if they do, they'll think nothing of it. So nineteen-year-old Reg was killed by an Auror. It happened, repeatedly. When the person on the other side of the wand is a wanted terrorist, you don't use Wingardium Leviosa, even if he is a teenager. And much of the time, the Ministry didn't publish these events. It was a war of misinformation as much as anything else. The Ministry had to live with the chaos that Voldemort created, so they tried to turn it against him."
"So these Aurors they keep talking about...they would have killed you?"
"Without a doubt."
"And now we're working with them?" John couldn't help asking.
Sherlock threw down his quill. "John. I don't think you understand the scope of the war Voldemort raged."
"I've been picking up bits and pieces," John said sardonically.
Sherlock bit his lip, then shoved the parchment toward John.
"Have a look, then."
So John did.
There are things too horrible to be seen or spoken. Things that go unrecorded in any books except histories. John had seen some of them in Afghanistan, during the war. He saw more of them here, in Sherlock's black, spidery scrawl. He saw his best friend at sixteen, witnessing them, and felt the world twist beneath him.
Sherlock saw him clutch at the desk and was at his side in a moment. "John?"
"Fine. I'm fine." John sank into a chair and let out a ragged breath. "I knew there were people in the world who would do such things, Sherlock. I just didn't know there were any who could."
"Such is 'progress' in warfare. Magic only complicates things."
"Dumbledore explained it to me. Sherlock, I'm not the one who went through these horrors. Are you all right?"
In John's experience with Sherlock, questions in this vein were ignored. He was startled, therefore, when Sherlock spoke after a moment's contemplation.
"No."
There was nothing John could do but nod.
"But there's no time," said Sherlock matter-of-factly. "Not to process sixteen years of memories. It can wait. My mind palace makes accommodations for such things. Right now my brother is in danger. Harry Potter, too, and anyone who gets between them."
"I thought you said Sirius was innocent!" John protested.
"He was, twelve years ago. Now? I'm not looking forward to a happy family reunion, John. He's probably out of his mind, after twelve years in Azkaban. There's no telling what he'll do; no how things have gotten twisted around in his head, or what his obsession with Harry Potter means. And if Fudge's thugs get to him before we do..."
Sherlock's silence left John no illusions about Sirius' chances. There was little more to say.
Except: "I want my gun."
"Your wish is my command," said a sardonic voice behind him. John whirled. Mycroft was there, holding a very familiar standard-issue Browning handgun.
"You're actually condoning this?" asked John hoarsely.
Mycroft shrugged. "I've made my way in the Wizarding World these fifteen years; why shouldn't you? You'll find that wizards very rarely see bullets coming. And they've never been tested on dementors. I admit I'm curious."
John took the weapon.
"Don't shoot unless to kill," Mycroft advised him. "Sherlock has less permanent alternatives where incapacitation is required. Sherlock," Mycroft fixed his eyes on his brother. "Is your Patronus functional?"
Sherlock guessed at the reason for the question, and his mouth hardened. "Fine."
"Show me."
"I'm not a child."
"Nor I a fool. The trauma you just underwent would have a lesser man sobbing on the floor, Sherlock. Show me the Patronus."
Sherlock clenched his jaw, then exhaled, quieting himself visibly. He raised his wand.
"Expecto Patronum!"
John jumped as something massive leapt from its end. It took a moment to make sense of the flashing coils: an enormous snake, made entirely of light coalesced, twisting and writhing in the air.
"Impressive," said Mycroft. Sherlock spared him a glance, letting the serpent dissipate into nothing.
"Satisfied?"
"Very much so."
"What was all that about?" John demanded.
"The ideal offense against dementors," said Mycroft. "And here is the defense." He pulled two large bars of dark chocolate from his jacket.
"I don't think I expected that," said John, taking one. "What's this then? Some sort of magical exploding-"
"It's chocolate," interrupted Sherlock. "The higher the cocoa content, the better. Antidote to dementor effects."
"You've got to be joking," said John, recalling what Dumbledore had told him about dementors.
"Why? Chocolate's endorphin-generating effects are well-known."
"Yeah, in mommy blogs."
"Knowledge can be found in strange places," interjected Dumbledore, sweeping in to pluck Sherlock's report from the desk. He scanned it slowly, expression grave.
"Sometimes even Mycroft," quipped Sherlock.
The headmaster looked up. "Are you prepared, John?"
"Almost," said John, a little dazed. "There's just one thing I still don't understand."
Mycroft gestured him on; Sherlock merely waited.
"It's why you always have to have a melodramatic name. 'Regulus Arcturus Black' is even worse than 'Sherlock Holmes'."
The corner of Mycroft's mouth twitched, and Sherlock glared.
"'Mycroft' is every bit as bad," he snapped.
"Albus Percival Wulfric Brian Dumbledore," said the headmaster apologetically to John's inquiring gaze.
John buried his face in his hands.
"I think I need to meet someone in this mad world named Harry Potter."
"We may end up doing just that," Sherlock said, flicking his wand casually at his long coat. John blinked hard. The change was subtle, but when the detective stood he was wearing long black robes that nearly swept the floor. He blended right in with the teachers.
"What do you think?" he asked Dumbledore. "Visiting Ministry worker? Auror?"
"With that scarf, you might pass for a Ravenclaw prefect," Dumbledore chuckled. John had to agree. With his overlong, curling hair, and the imposing coat swapped for simple robes, Sherlock looked extremely young.
"Auror will give me authority, and if anyone from the Ministry does call—"
"I'll tell them you're a consulting detective," Dumbledore suggested.
"I was going to say 'lie between your teeth', but I like that better."
"I shall inform the staff. However, prudence would dictate an alteration in your appearance." The headmaster pointed his wand at Sherlock, and a moment later his curls were a light brunette. "We don't want anyone wondering why the stranger wandering our halls looks so very like our escaped fugitive. For that matter, take this."
And he handed over what looked like a wad of shimmering, silvery material.
"I'll try to avoid old friends," said Sherlock, inspecting the wad in appreciation. "Ah, John." He waved his wand again, this time in John's direction, and the doctor looked down to find himself sporting long robes that matched Sherlock's.
Dumbledore surveyed them both approvingly.
"Mycroft, I do believe we'll need another of your ingenious talismans for John."
McGonagall entered the room, most unluckily, as Dumbledore was saying this.
"Albus, you don't mean to say…"
"Yes, Minerva, I do," he replied calmly.
"Hardly a Muggle has set foot within Hogwarts, let alone been given the grand tour! And it isn't just the castle either, they'll have to search the grounds. It isn't safe!"
John had no time to voice his indignation before Sherlock's deep laugh stopped everyone short. "I assure you, John can take care of himself."
"But…"
"And if he can't, I will."
"Regulus, I hardly think it's for you to say…"
"That's true, Professor." The shift was, as ever, mercurial; Sherlock's tone now matched his stare, layered in ice. "It is for the headmaster and deputy headmistress to determine whether you are illegally attempting to detain Regulus Black, whose innocence has been legally proven before the Chief Warlock of the Wizengamot, or engaging the services of consulting detective Sherlock Holmes. If the former, I will call upon the headmaster," he gestured toward Albus, "to witness my innocence in court, and I bid you good luck in finding your mass-murderer. If the latter, I will give the case my best effort and retain the help of my colleague Doctor Watson. I await your decision."
Instead of cowering, Minerva stood straighter at these words. "Regulus, you can't be—then for pity's sake stay out of the forest! At the very least, warn him about the dementors!"
"They have," John said. "Sort of."
"And stay away from the Whomping Willow—"
"Is that what it sounds like?"
"It's a long time since the giant squid has attacked anyone, but—"
"Are you actually serious?"
"And do be sure not to rile the centaurs—"
"Is this a school or a war zone?"
Sherlock smiled, and the sight was far more chilling than McGonagall's warnings.
"Yes," he said. "How I've missed it."
And he led the way out of Dumbledore's office.