Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Harry had kept the emergency flares and the oxyacetylene welding torch and fuel tank, since you couldn't just Transfigure things that were to be burned.

(Be prepared, as through life you march along...)

Mary's Place.

After the waitress had taken their order and bowed to them and left the room, Professor Quirrell had performed only four Charms, and then they'd talked about nothing of any vast consequence, just Professor Quirrell's complex thesis about how the Dark Lord's curse on the Defense position had led to the decline of dueling and how this had changed social customs in magical Britain. Harry listened and nodded and said intelligent things, while he tried to control the pounding of his heart.

Then the waitress came in again bearing their food, and this time, a minute after the waitress had departed, Professor Quirrell gestured for the door to close and lock, and began to speak twenty-nine security Charms, one of the ones in Mr. Bester's sequence being left out this time, which somewhat puzzled Harry.

Professor Quirrell finished his Charms -

- stood up from his chair -

- blurred into a green snake, banded in blue and white -

- hissed, " Hungry, boy? Eat your fill sswiftly, we sshall need both sstrength and time. "

Harry's eyes were a bit wide, but he hissed, " I ate well at breakfasst, " and then rapidly began forking noodles into his mouth.

The snake watched him for a moment, with those flat eyes, and then hissed, " Do not wissh to explain here. Prefer to be elssewhere firsst. Need to leave unobsserved, without ssign we have ever departed room. "

" Sso no one can track uss, " hissed Harry.

" Yess. Do you trusst me that much, boy? Think before ansswer. I will have important requesst of you, which requiress trusst; if ssay no regardlesss, then ssay no now. "

Harry dropped his gaze from the snake's flat eyes, and looked back down at his sauce-coated noodles, and ate another bite, then another, while he thought.

The Defense Professor... was an ambiguous figure, to put it mildly; Harry thought he had unraveled some of his goals, but others remained mysterious.

But Professor Quirrell had knocked down two hundred girls to stop the ones summoning Harry. Professor Quirrell had deduced that the Dementor was draining Harry through his wand. The Defense Professor had saved Harry's life, twice, in a two-week period.

Which could mean that the Defense Professor was just saving Harry for later, that there were ulterior motives. Indeed, it was certain that there were ulterior motives. Professor Quirrell wasn't doing this on a whim. But then Professor Quirrell had also seen Harry taught Occlumency, he had taught Harry how to lose... if the Defense Professor wanted to make some use of Harry Potter, it was a use that required a strengthened Harry Potter, not a weakened one. That was what it meant to be used by a friend, that they would want the use to make you stronger instead of weaker.

And if there was sometimes a cold atmosphere about the Defense Professor, bitterness in his voice or emptiness in his gaze, then Harry was the only one who Professor Quirrell allowed to see it.

Harry didn't quite know how to describe in words the sense of kinship he felt with Professor Quirrell, except to say that the Defense Professor was the only clear-thinking person Harry had met in the wizarding world. Sooner or later everyone else started playing Quidditch, or not putting protective shells on their time machines, or thinking that Death was their friend. It didn't matter how good their intentions were. Sooner or later, and usually sooner, they demonstrated that something deep inside their brain was confused. Everyone except Professor Quirrell. It was a bond that went beyond anything of debts owed, or even anything of personal liking, that the two of them were alone in the wizarding world. And if the Defense Professor occasionally seemed a little scary or a little Dark, well, that was just the same thing some people said about Harry.

" I trusst you, " hissed Harry.

And the snake explained the first stage of the plan.

Harry took a final forkful of noodles, chewed. Beside him, Professor Quirrell, now in human form again, was eating his soup placidly, as though nothing of special interest were occurring.

Then Harry swallowed, and in the same moment stood up from his chair, already feeling his heart start to hammer hard in his chest. The security precautions they were taking were literally the most stringent possible...

"Are you ready to test it, Mr. Potter?" Professor Quirrell said calmly.

It wasn't a test, but Professor Quirrell wouldn't say that, not out loud in human speech, even in this room screened to the limit that Professor Quirrell had secured with further Charms.

"Yep," Harry said as casually as he could.

Step one.

Harry said "Cloak" to his pouch, drew forth the Cloak of Invisibility, and then unstuck the pouch from his belt and threw it toward the other side of the table.

The Defense Professor stood up from his own seat, drew his wand, bent down, and touched his wand to the pouch, murmuring a quiet incantation. The new enchantments would ensure that Professor Quirrell could enter the pouch on his own in snakeform, and leave it on his own, and hear what went on outside while he was in the pouch.

Step two.

As Professor Quirrell stood up from where he'd bent over by the pouch, and put away his wand, his wand happened to point in Harry's direction, and there was a brief crawling sensation on Harry's chest near where the Time-Turner lay, like something creepy had passed very close by without touching him.

Step three.

The Defense Professor turned into a snake again, and the sense of doom diminished; the snake crawled to the pouch and into it, the pouch's mouth opening to admit the green shape, and as the mouth closed again behind the tail, the sense of doom diminished further.

Step four.

Harry drew his wand, being careful to stand still as he did it, so that the Time-Turner would not move from where Professor Quirrell had anchored the hourglass within the shell in its current orientation. " Wingardium Leviosa ," murmured Harry, and the pouch began to float toward him.

Slowly, slowly, as Professor Quirrell had instructed, the pouch began to float toward Harry, who waited alert for any sign the pouch was opening, in which case Harry was to use the Hover Charm to propel it away from him as fast as possible.

As the pouch came within a meter of Harry, the sense of doom returned.

As Harry reattached the pouch to his belt, the sense of doom was stronger than it had ever been, but still not overwhelming; it was tolerable.

Even with Professor Quirrell's Animagus form lying within the extended space of the pouch resting on Harry's very hip.

Step five.

Harry sheathed his wand. His other hand still held the Cloak of Invisibility, and Harry drew that cloak over himself.

Step six.

And so in that room shielded from every possible scrying, which Professor Quirrell had personally and further secured, it was not until after Harry was wearing the true Cloak of Invisibility that he reached beneath his shirt and twisted the outer shell of the Time-Turner just once.

The Time-Turner's inner hourglass stayed anchored and motionless, the setting twisted around it -

The food vanished from the table, the chairs leaped back into place, the door sprang open.

Mary's Room was deserted, as it should have been, because Professor Quirrell had earlier contacted Mary's Place under a false name to inquire whether the room would be available at this hour - not to reserve it, not to place a canceled reservation that might be noted, but only to inquire.