Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Tick.

Harry looked over at where the Ravenclaws had clustered, he didn't see Hermione but then everyone was packed tightly-enough together that you wouldn't expect to see smaller students through the crowd, amid the upper-years.

Tick.

Harry then looked over at the Hufflepuffs to see if he could spot Neville, and even though Neville was standing behind a much taller student, Harry's visual processing managed to spot him almost immediately. Hermione wasn't with the Hufflepuffs either, not that Harry could see - and she certainly wouldn't be with the Slytherins -

Tick.

Harry pushed his way through the packed crowd, stepping beside or around older students and in one case just ducking between their legs, until he was standing among the Ravenclaws and could definitely verify that, nope, no Hermione.

Tick.

"Hermione Granger!" Harry said loudly. "Are you here?"

Nobody answered.

Tick.

Somewhere in the back of his mind was a rising sense of horror, as other parts of him tried to decide exactly how much to panic. The first Defense class of the year was rather fuzzy in Harry's mind, but he distantly remembered something about trolls being able to track prey that was alone and undefended.

Tick.

Another track of thought searched frantically through inchoate possibilities, what could he do exactly? It wasn't 3pm yet so he couldn't reach this now using his Time-Turner. Even if he could sneak out of the room - there had to be some way to put on his Cloak without being noticed, some sort of distraction he could use - he had no idea where Hermione was, and Hogwarts was huge.

Tick.

Another part of his mind tried to model possibilities. From what that other student had said, trolls weren't silent predators, they were noisy -

Hermione won't have any idea it's a troll, so she'll go investigate the noise. She's a heroine, isn't she?

- but Hermione now had an invisibility cloak and a broomstick in her pouch. Harry had insisted on that part for both her and Neville, and Professor McGonagall had told him it'd been done. That ought to be enough to let Hermione get away, even if she was lousy on a broomstick. All she had to do was get onto a section of roof, it was a clear day and sunlight was supposed to be bad for trolls somehow, Harry remembered that part and therefore Hermione would remember it exactly. And surely, even if Hermione wanted to prove herself again, she couldn't possibly be dumb enough to attack a mountain troll.

Tick.

She wouldn't.

Tick.

That just wasn't her.

Tick.

And then it occured to Harry that somebody had previously tried to frame Hermione Granger for murder using Memory Charms. Had done so inside Hogwarts, without setting off any alarms. And had arranged for Draco to die slowly enough that it wouldn't set off the wards until at least six hours later when nobody could use a Time-Turner to check. And that whoever was clever enough to infiltrate a troll past the ancient wards of Hogwarts without the Headmaster coming to investigate the strange creature, could be clever enough to also take the obvious step of jinxing Hermione's magic items...

Tick.

There was a part of him that felt something like slowly rising panic as perspective shifted, a Necker Cube changing orientation, what the hell had Harry been thinking, letting Hermione and Neville be kept inside Hogwarts just because of them being given a few stupid trinkets, that wasn't going to stop anyone who wanted to kill them .

Tick.

Another part of his mind put up resistance, that possibility wasn't certain , it was complex and the probability could easily be under 50%. It was easy to imagine going into a huge panic in front of everyone and then Hermione getting back from the washrooms outside the Great Hall. Or if the troll ended up not going anywhere near her... like in the story of the boy who cried wolf, nobody would believe him the next time if she really was in trouble; it could use up reputational credit that he would later need for something else...

Tick.

Harry recognized an instance of the fear-of-embarrassment schema that stopped most people from ever doing anything under conditions of uncertainty, and squashed it down hard. Even then it was strange how much willpower it took to muster the decision to shout out loud in front of everyone, if he just hadn't seen Hermione in the crowd it was going to be embarrassing...

Tick.

Harry drew in a deep breath and shouted as loudly as he could, "Hermione Granger! Are you here?"

The students all turned to look at him. Then some of them turned around to look around themselves. The noise around the room went down in volume as some conversations stilled.

"Has anyone seen Hermione Granger since - since around ten-thirty today or so? Does anyone have any idea where she might be?"

The background babble stilled further.

Nobody raised their voice to shout anything at him, in particular not, Don't worry, Harry, I'm right here.

"Oh, Merlin," somebody said from nearby, and then the background babble started up again, taking on a new and excited tone.

Harry stared down at his hands, shutting out the yammering and tried to think, think, THINK -

Tick.

Tick.

Tick.

Susan Bones and a redheaded boy with a battered-looking wand both shoved their way through the crowd to Harry at the same time.

"We've got to let the Professors know somehow -"

"We've got to go find her -"

"Find her?" Susan snapped, rounding on the other boy. "How'll we do that , Captain Weasley?"

"We'll go off and look for her!" Ron Weasley snapped back.

"Are you nuts? There's already Professors searching the hallways, what makes you think we've got any better chance than them of running across General Granger? Only we'll get eaten by the troll! And then expelled!"

It was odd, how sometimes hearing bad ideas made the right idea obvious by contrast.

" All right everyone! Listen up! "

People turned to look.

" QUIET! EVERYONE! SHUT UP! "

Harry's throat ached after that, but he had everyone's attention.

"I have a broomstick," Harry said as loudly as he could manage with his throat still hurting. He'd remembered Azkaban, and the broomstick which had only sat two, when he'd requested one that could carry three. "It's a 3-seater. I need one seventh-year from the armies to come with me. We're going to fly through the hallways as fast as possible looking for Hermione Granger, pick her up, and come back immediately. Who's with me?"

The Great Hall became entirely silent, then.

Students glanced at each other uneasily. The younger students looked expectantly at the older students, while they in turn turned to look at the students who were guarding the perimeter. Most of those were staring straight ahead, pointing their wands just in case the troll picked that moment to burst through a wall.

No one moved.

No one spoke.

Harry Potter spoke again. "We're not going to fight the troll. If we see it we'll just fly away and there's no way it'll be able to keep up with us on a broomstick. I'll take responsibility for squaring it with the administration. Please. "

People went on looking at other people.

Harry stared at the silent crowd, the dozen seventh-years looking sternly outward, feeling the coldness coming over him. Somewhere in the back of his mind, Professor Quirrell was laughing scornfully and mocking the idea that ordinary fools would ever do something useful of their own will, without a wand pointed at their heads...