Harry Potter and the Methods of Rationality

"Innervate," said Hermione, pointing her wand at Daphne, whose body she hadn't been able to see before; and Lavender pointed her wand at Hannah's body and said the same.

Hannah's eyes opened and she tried frantically to roll to her feet, but collapsed to the ground halfway through.

"It's okay, Hannah!" said Lavender. "We won."

"We what?" said Hannah from her little heap on the floor.

Daphne hadn't stirred, but Hermione could see her chest rising and falling, and the breathing rhythm looked normal enough. "I think she's okay," said Hermione, "but -" She took a moment to swallow, her mouth was still dry. This had all gotten way, way, way out of hand. "I think we ought to take Daphne to Madam Pomfrey's..."

"Sure, sure, just give me a second here and I'll probably be fine," said Parvati.

"Excuse me," Hannah said in a tone that was polite, but firm. "How did we win? And why does the ceiling look all melty?"

There was a pause.

"Susan did it," said Tracey.

"Yeah," said Parvati, voice only slightly shaky as she stood up and started to brush off her red-trimmed robes, "it turns out that Susan Bones is the Heir of Hufflepuff and she's opened up the long-lost entrance to Helga Hufflepuff's Chamber of Hard Work and Practice."

"Huh?" said Hannah, who was feeling over herself as if to make sure all her body parts were still there. "I thought that was just something Professor Sprout says to teach us an Important Moral Lesson - Susan is?"

Slowly, Hermione was beginning to feel a bit more together. It hadn't really been more than thirty seconds of extreme terror, at least not the parts she'd been conscious for. "Actually," Hermione said carefully, as her mind started to work again, "I'm pretty sure that is just something Professor Sprout says, it wasn't in Hogwarts: A History or anywhere else I've read -"

"She's a double witch!" shouted Tracey, her voice so high it cracked. "She is! She's one of them! She's been this whole time!"

"What?" yelled Parvati, twisting around to look at Tracey. "That is the looniest thing -"

"Of course!" said Lavender, now all the way on her feet and starting to bounce up and down with excitement. "I should've realized!"

"Susan's a what?" said Hermione.

"A double witch!" said Tracey.

"You see," said Lavender, speaking very rapidly, "There've always been stories, about these children who are born as super magicians who can cast spells no one else can, and there's a whole secret school hidden inside Hogwarts with classes that only they can see and go to -"

"Those are just stories!" yelled Parvati. "That's not how real life works! I mean, sure, I read those books too -"

"Just a minute, please," said Hermione. Maybe her mind was feeling a little slow after all. "You mean even though you already get to go to a magical school and everything, you still want to go to a double magical school?"

Lavender looked at her, puzzled. "What?" said Lavender. "Who wouldn't want to have super extra magical powers? It would be like this whole amazing destiny and everything! It'd mean you were special!"

Hannah nodded to that, looking up from where she'd crawled to Daphne's side and was checking the girl for broken bones. "I wish I was a double witch," Hannah said, and then, sounding a little sadder, "though I don't believe there is any such thing, really... what did you see Susan do, exactly? I mean, are you sure you weren't just seeing things after getting stunned?"

Hermione truly, truly couldn't find any words at this point.

"Oh, no," said Tracey. The Slytherin girl spun around to look at the entrance to the corridor, her robes fluttering around her. "Oh no! We've got to get out of here! We've got to get away before Susan comes back with someone who can Super-Memory-Charm us!"

"Susan wouldn't do that!" said Parvati. "I mean, if there even was -"

"WHAT'S GOING ON HERE?" roared a high-pitched squeaky voice, as Professor Flitwick stormed into the partially melted corridor like a small, dangerously compressed package of pure academic fury, an ashen-faced Padma gasping along behind him.

"What happened?" Susan blurted to the girl who looked exactly like her, except for the scorched robes damp with sweat.

"Ooh, great question!" said the other Susan Bones as she rapidly skinned off what was left of her borrowed clothes. A moment later the girl began to Metamorphose back into her more accustomed form of Nymphadora Tonks. "Sorry but I couldn't think of anything myself so you've got about three minutes to decide on an answer to that -"

As Daphne Greengrass observed afterward with some acidity, the flaw in Hermione's cunning plan to make sure that House points were taken evenly from all four Houses if they got caught, was that it didn't work on detentions.

They'd all agreed to keep their mouths shut about Susan's mysterious powers - even Tracey, after Susan threatened to have her Super-Memory-Charmed if she didn't promise. Unfortunately, they discovered at dinnertime that someone had forgotten to tell the bullies about their agreement, and also that Susan Bones had sacrificed her soul to dreadful forbidden powers which now inhabited the hulk of her body and that was why they'd all gotten detention.

"Hermione?" Harry Potter said to her from beside her at the dinner table, his voice very tentative. "Please don't