Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Only time for one desperate wish that an innocent man should not die -

And a blazing silver figure stood before the Auror.

Stood there just a fraction of a second before the green light struck home.

Bahry was twisting frantically aside, not knowing if he was going to make it -

His eyes were focused on his opponent and his onrushing death, so Bahry only briefly saw the outline of the brilliant silhouette, the Patronus brighter than any he'd ever seen, saw it just barely long enough to recognize the impossible shape, before the green and the silver light collided and both lights vanished, both lights vanished, the Killing Curse had been blocked , and then Bahry's ears were pierced as he saw his terrible opponent screaming, screaming, screaming, clutching at his head and screaming, starting to fall as Bahry was already falling -

Bahry hit the ground, falling from his own frantic lunge, and his dislocated left shoulder and broken rib screamed in protest. Bahry ignored the pain, managed to scramble back to his knees, brought up his wand to stun his opponent, he didn't understand what was happening but he knew that this was his only chance.

" Stupefy! "

The red bolt struck out toward the man's falling body, and was torn apart in midair and dissipated - and not by any shield. Bahry could see it, the wavering in the air that surrounded his fallen and screaming opponent.

Bahry could feel it like a deadly pressure on his skin, the flux of magic building and building and building toward some terrible breaking point. His instincts screamed at him to run before the explosion came, this was no Charm, no Curse, this was wizardry run wild, but before Bahry could even finish getting to his feet -

The man threw his wand away from himself (he threw away his wand!) and a second later, his form blurred and vanished entirely.

A green snake lay motionless on the ground, unmoving even before Bahry's next stunner spell, fired in sheer reflex, hit it without resistance.

As the dreadful flux and pressure began to dissipate, as the wild wizardry died back down, Bahry's dazed mind noticed that the scream was continuing. Only it sounded different, like the scream of a young boy, coming from the stairs leading down to the next lower level.

That scream choked off too, and then there was silence except for Bahry's frantic panting.

His thoughts were slow, confused, disarrayed. His opponent had been insanely powerful, that hadn't been a duel, it had been like his first year as a trainee Auror trying to fight Madam Tarma. The Death-Eaters hadn't been a tenth that good, Mad-Eye Moody wasn't that good... and who, what, how in the name of Merlin's balls had anyone blocked a Killing Curse?

Bahry managed to summon the energy to press his wand against his rib, mutter the healing spell, and then press it again to his shoulder. It took more out of him than it should have, took far too much out of him, his magic was within a bare breath of utter exhaustion; he didn't have anything left for his minor cuts and bruises or even to reinforce the scraps left of his shielding. It was all he could do not to let his Patronus go out.

Bahry breathed deeply, heavily, steadied his breath as much as he could before he spoke.

"You," Bahry said. "Whoever you are. Come out."

There was silence, and it occurred to Bahry that whoever it was might be unconscious. He didn't understand what had just happened, but he'd heard the scream...

Well, there was one way to test that.

"Come out," said Bahry, making his voice harder, "or I start using area-effect curses." He probably couldn't have managed one if he'd tried.

"Wait," said a boy's voice, a young boy's voice, high and thin and wavering, like someone was holding back exhaustion or tears. The voice now seemed to be coming from closer to hand. "Please wait. I'm - coming out -"

"Drop the invisibility," growled Bahry. He was too tired to bother with anti-Disillusionment Charms.

A moment later, a young boy's face emerged from within an unfolding invisibility cloak, and Bahry saw the black hair, the green eyes, the glasses, and the angry red lightning-bolt scar.

If he'd had twenty fewer years of experience under his belt he might have blinked. Instead he just spat something that he probably shouldn't ought to say in front of the Boy-Who-Lived.

"He, he," the boy's wavering voice said, his young face looked frightened and exhausted and tears were still trickling down his cheeks, "he kidnapped me, to make me cast my Patronus... he said he'd kill me if I didn't... only I couldn't let him just kill you..."

Bahry's mind was still dazed, but things were slowly starting to click into place.

Harry Potter, the only wizard ever to survive a Killing Curse. Bahry might have been able to dodge the green death, he'd certainly been trying, but if the matter came up before the Wizengamot, they'd rule it was a life debt to a Noble House.

"I see," Bahry said in a much gentler growl. He started to walk toward the boy. "Son, I'm sorry for what you've been through, but I need you to drop the cloak and drop your wand."

The rest of Harry Potter emerged from invisibility, showing the sweat-soaked blue-trimmed Hogwarts robes, and his right hand clutching an eleven-inch holly wand so hard his knuckles were white.

"Your wand," Bahry repeated.

"Sorry," whispered the eleven-year-old boy, "here," and he held out the wand toward Bahry.

Bahry barely stopped himself from snarling at the traumatized boy who'd just saved his life. Instead he overrode the impulse with a sigh, and just stretched out a hand to take the wand. "Look, son, you're really not supposed to point a wand at -"

The wand's end twisted lightly beneath Bahry's hand just as the boy whispered, " Somnium ."

Harry stared at the Auror's crumpled body, there was no sense of triumph, just a crushing sense of despair.

(Even then it might not have been too late.)

Harry turned to look at where the green snake lay motionless.

" Teacher? " hissed Harry. " Friend? Pleasse, are you alive? " An awful fear was taking hold in Harry's heart; in that moment he had entirely forgotten that he'd just seen the Defense Professor try to kill a police officer.

Harry pointed his wand at the snake, and his lips even began to shape the word Innervate , before his brain caught up with him and screamed at him.

He didn't dare use magic on Professor Quirrell.

Harry had felt it, the burning, tearing pain in his head, like his brain was about to split in half. He'd felt it, his magic and Professor Quirrell's magic, matched and anti-harmonized in a fulfillment of doom. That was the mysterious terrible thing that would happen if Harry and Professor Quirrell ever got too close to each other, or if they ever cast magic on each other, or if their spells ever touched, their magic would resonate out of control -

Harry stared at the snake, he couldn't tell if it was breathing.

(The last seconds ticked away.)

He turned to stare at the Auror, who had seen the Boy-Who-Lived, who knew.

The full magnitude of the disaster crushed in on Harry like a thousand hundred-ton weights, he'd managed to stun the Auror but now there was nothing left to do, no way to recover, the mission had failed, everything had failed, he had failed.

Shocked, dismayed, despairing, he didn't think of it , didn't see the obvious, didn't remember where the hopeless feelings were coming from, didn't realize that he still needed to recast the True Patronus Charm.

(And then it was already too late.)

Auror Li and Auror McCusker had rearranged their chairs around the table, and so they both saw it at the same time, the naked, skeletally thin horror rising up to hover outside the window, the headache already hitting them from seeing it.