"Hello, David," said Albus Dumbledore calmly. The old wizard's eyes glinted like sapphires. His robes were a deep indigo-purple, padded and seeming to follow his movements closely, such that they would not obstruct him. Fawkes perched on his shoulder, space-black eyes shining with righteous courage, like an unwavering flame. In Dumbledore's right hand was a long, slender wand of dark-grey wood, in his left the Line of Merlin Unbroken, and his magic was gathered about him like a cloak.

"Albus," replied the Defence Professor, inclining his head. David Monroe's icy eyes met the Chief Warlock's unflinchingly, his robes dark and reserved, a creature of cursed fire behind him, his own wand in his hand.

Dumbledore's eyes gave the sudden impression of X-raying the Defence Professor. "I have kept my promise, Quirinus, to make no enquiry into your identity, and yet one cannot help what one sees. It was Harry Potter's nature that convinced me, in the end." The eyes twinkled, and he spoke as though conversing over drinks. " I was most amused to find the boy forged in Lord Voldemort's image before me, blackmailing me for the sake of his fellow students. Such dark intellect, harnessed for the sake of Lily and James and Michael and Petunia's warmth and love! Tom, in his hubris, created a good Voldemort to oppose him."

Monroe did not look like he was enjoying a casual conversation. "It rather speaks volumes," he said dryly, "that it took Voldemort's own help for you to have a chance to defeat him."

Dumbledore smiled. "Oft evil will shall evil mar, as Tolkien put it. I wonder what Harry made of that observation... you two really are quite alike, you know."

Monroe smirked. "I shall take that as a compliment. Just this day I have seen our young associate unravel the Words of False Comprehension. Oh, and we two were the ones who seized Bellatrix Black from Azkaban."

Dumbledore nodded. If he was surprised at either revelation, he did not show it. "My own Patronus identified Harry's as the one that it detected in Azkaban. May I ask your intended purpose?"

Dumbledore's calmness and politeness would have set Harry on edge before, but he recognised that impulse as a habit inherited from Riddle, and discounted it.

There was a definite edge to Quirrell's voice. "Yes, you who would never think of sharpening a Hufflepuff's bones into spears." He reached into his robes and drew forth a bone-white wand that seemed horribly familiar, with a black ribbon tied around it. Thirteen and a half inches, yew, phoenix feather core... "I sought to find where Bellatrix had hidden the Dark Lord's wand. If it comes to it, I shall use a Portkey to drop it into the central pit of Azkaban."

Professor Dumbledore raised his eyebrows. "I would call that inhumane, for any other than he."

Quirrell's tone was acid. "Inhumane. And yet you withhold the Philosopher's Stone from the world. Yes, Mr. Potter accompanied me here, because copies of the Dark Lord or not, we both at least comprehend the elementary ethical axiom that death is bad."

The old wizard sighed. "Quirinus, the Stone, please."

"Ah." There was no shift in the stance of either of the two, but there was sudden danger in the air. "You truly do not know what the Stone does, then. Frank and Alice-"

"I am resolved," said the Chief Warlock with iron in his tone, "to deafen myself to such claims, for Tom is too persuasive and too cunning for my judgement to be secure."

Professor Quirrell passed a hand over his eyes. "That is madness. There is a reason we call such paranoia an illness-"

In mid-sentence, the Defence Professor aimed his wand.

It happened before Harry could react, before he could shout a warning, before he could form the words of the Patronus Charm.

The Killing Curse struck Albus Dumbledore squarely in the chest.

The old wizard did not blink.

Fawkes spread his wings and cawed, the warm yet warning cry of the true phoenix. The dark-grey wand rose in front of Dumbledore like a sword, a wave of white fire ran up it and burst from the tip in a shower of sparks, and it was like Harry heard a sudden song, a paean of glory and battle, a hymn of victory.

The Hallowed Wand. Whilst he held that, Dumbledore was no more vulnerable than a Dementor - that was the part of Death's power bound into the Elder Wand.

The Peverells had had a taste for flashiness, it seemed.

Harry had thought he'd seen advanced magic before, but this he couldn't follow at all, it was just too far over his head, though he noted that Quirrell was moving like a Muggle martial artist but with inhuman grace, hissing echoing Words of Power, whereas Dumbledore was mostly standing his ground, occasionally waving the Elder Wand or murmuring something that would always overcome Quirrell's magic and show him gritting his teeth and gripping his own wand with both hands to resist.

Quirrell gestured, and the black-red-white false phoenix hissed and streaked at Fawkes.

Horror-struck, Harry waited for the creature of life and rebirth to be cursed into permanent death.

Fawkes screamed, and Professor Quirrell staggered. Dumbledore bellowed something ancient and terrible, and suddenly Fawkes was sheathed in golden fire, and he met his mockery in midair, talons blazing.

Quirrell began to incant something incomprehensible, cold and harrowing, but Dumbledore made a cutting motion and the rising sense of power vanished.

"The most powerful wizard alive" had most certainly not been an exaggeration.

Even if Harry had been able to make himself heard over the noise of the duel, even if the Mirror had let sound through in that direction, he wouldn't have known what to say. Shut up and multiply - if Quirrell gets the Stone it could save hundreds of thousands of lives -

Do we trust Quirrell? asked Slytherin.

Dumbledore doesn't know what the Stone does. Maybe he'd allow it to be used in a hospital if he did, argued Gryffindor.

Dumbledore raised his wand and swung it like a cricket bat, speaking words with sounds he shouldn't have been able to make and Harry shouldn't have been able to hear. The force of the resulting spell was such that Harry felt it even through the Mirror, setting his teeth on edge and his hair on end. Quirrell's eyes widened, and he was forced to conjure a burnished silver shield, which showed no sign of damage when the spell struck, but rang with a pure, chilling note.

With a bolt of quicksilver and a sound like gunshot, Quirrell managed to force Dumbledore onto his back foot, but it was obviously hopeless. Quirrell had Slytherin's lore, and all the Dark Lord's hoarded knowledge on top of that, but Dumbledore was even more skilful, not to mention invulnerable.

"Singularis Nex!"

"Lux Argentus."

A bolt of white lightning impacted upon a mote of pure blackness, which swelled and burst, reforming into a swarm of daggers that converged on Quirrell, who popped like a soap bubble and appeared by his opponent's side. He waved his wand and Dumbledore was surrounded by a vast sphere of solid steel, glowing with enchantment, which Quirrell tapped with the Philosopher's Stone.

For the briefest moment, Harry thought Monroe might have won.

Then the shell glowed cherry-red and white-hot, and the solid steel consumed itself. Fawkes gave a victorious cry, and shredded the false phoenix into scattered flames. The scraps of Fiendfyre danced ineffectively around Dumbledore.

"It was foolish of you to try this, David," came the old voice, gently.

"Think you can last another twenty hours, Albus?" spat Monroe.

Lose, Professor, begged Harry silently, if there's ever a time to lose it's when the enemy is literally invincible...

With a whip-cracking motion, a line of fire impacted Quirrell's shields and slammed him into the Mirror-wall. Dumbledore advanced on him, wand level.

The Defence Professor vanished, and did not reappear.

What the-

PAIN.

Darkness coiled around Harry, holding him and binding him so deeply that he didn't know where he ended and the darkness began.

Harry doubled over, crying out, and then it was over as Quirrell reappeared next to him, covered too by the Cloak of Invisibility, subject no more to the Mirror's power.

Harry could feel it, feel the magic start to resonate, but it was nothing like as bad as in Azkaban. Possession doesn't count as being anywhere near as powerful as the Killing Curse, clearly.

Quirrell slashed his wand like a dagger over his left wrist, and his hand winked out of existence and in its place arose a shimmering red barrier over the Mirror of Erised.

The shreds of Fiendfyre burned through the wall of Hogwarts and up through the earth.

The sense of doom, previously muted, rose to intolerable heights as Quirrell's arm linked around Harry's, shielded only by robes, and then they shot out and up through the tunnel, taking them beyond Hogwarts' wards.

Distantly, Harry heard Dumbledore shatter Quirrell's ward, and the old wizard reappeared, borne up by Fawkes-

A tug behind his navel, and the world vanished.