John took a deep breath. The four of them sat in a cluster of maroon leather armchairs around the flickering flames, which had mercifully reassumed their natural hue and proportions. Raindrops pounded leadenly against the two vaulted, paned windows behind the headmaster's desk. Squinting through them, John could make out the stormy morass looming above a green smudge of forest, as though threatening with destruction all he had ever assumed about the world. He tried not to think too much about the other things visible from the window.
"So let me get this straight," he said, eyes falling shut as he attempted to dredge the conversation's details from the lunatic realm where they belonged, and fit them into the context of reality. "Sherlock didn't actually grow up a Holmes; he's a wizard with a name even weirder than 'Sherlock'—"
Sherlock smiled unexpectedly.
"—who attended Hogwarts School of Witchcraft and Wizardry, which is a secret castle in the north of Britain—"
"Wherein you now sit," put in Dumbledore.
"And he was on the run from the Ministry of Magic, which by the way exists—"
"Not exactly on the run," said Sherlock dismissively. "I didn't do anything criminal."
"So far as we know." Mycroft was unconvinced.
"So far as I know."
"Ah yes," said John. "You're an amnesiac, too. I'd forgotten that bit." Sherlock snorted.
"Yes, I'm certain Mycroft will be able to enlighten us all as to how that occurred."
Mycroft imparted his least sincere smile and leaned against the desk, tapping his umbrella against a well-polished shoe. "In part."
"Then pray share what you do know," said Albus. "Reg—Sherlock has every right to know."
"First of all," said Mycroft awkwardly, after a pause, "everything I did was for your good, Sherlock. I do consider you my brother."
Sherlock's reply left no one in any doubt as to what he thought of this beginning.
"Get on with it."
"There are reasons—it may not be wise to do so at once. Sherlock, I am concerned about—"
"I HAVE HAD ENOUGH OF YOUR CONCERN!"
Everyone jumped, staring at Sherlock, who was on his feet with serpentine swiftness, ordinarily aloof features twisted in an inhuman snarl. John felt a cold twinge in his stomach. It was true that Sherlock had been on edge as of late, and his moods were often mercurial, but the façade—if façade it was—of irritable detachment rarely slipped during dealings with his brother. Only Mycroft appeared unsurprised by the outburst, though the collapse of his shoulders against leather spoke of sudden and uncharacteristic weariness, of uncertainty in the face of a day long held in dread. He closed his eyes and began again.
"Believe me, Sherlock, I—"
John's soldier's sense began buzzing almost imperceptibly at the base of his skull just before the lights began flickering. His left hand settled stone-still against his side.
"No, believe me," Sherlock hissed, fixing Mycroft with a gaze that could almost have spitted him to the wall. "If I do not have the full story, and the memories you have stolen from me, within the hour, you may forget our games of brotherly love and consider me your enemy."
The lights flicked off and on again, more violently; the window panes rattled in their frames, the whole room seeming to tremble under a silent pulse of energy. Dumbledore tapped his wand against the desk, his gaze inscrutable as he regarded his old student. Mycroft seemed to turn to stone as Sherlock finished.
"And that, I assure you, you do not want."
Mycroft opened his mouth again but stopped, arrested by the sight of Sherlock's left sleeve, which was smoking slightly. The next moment Sherlock felt a pain as piercing as though a hot iron were branding his skin, and ripped his cuff open. Coming into livid relief on his forearm was the image of a skull, black and grotesque, with a twisting serpent protruding from its mouth.
"That wasn't there before," said John automatically, turning to Dumbledore for an explanation. The headmaster, however, was silent. An expression of intense sadness passed over his face.
Sherlock caught his breath.
"I remember this," he said in a low voice. "Professor," looking up. "What does it mean?"
Dumbledore sighed deeply and turned to Mycroft. "The facts, please, Mr. Holmes, and leave nothing out. I will fill in the rest as far as I know it."
Mycroft began.