Disclaimer: The time derivative of Harry Potter is JK Rowling's writing habits.

Parts of this chapter have been quoted from Harry Potter and the Philosopher's Stone.

A/N: Yes, I know there's a lot of quoted material in this chapter. So far, Hermione's different behaviour hasn't spilt over much into the rest of the story, and this chapter is more of a reaction shot. But don't worry; things will start to really start to diverge in the next chapter, probably with no more quoted material from now on.

Chapter 5

Hermione wandered around the grounds with her roommates for a little while that afternoon, but she was distracted the entire time. She had a hard time focusing on her work that evening, too. She looked around at the castle walls and started questioning everything, started trying to measure everything in her head.

The thing that everyone kept telling her kept echoing in her mind: "The castle changes too much to make a map."

She waited till the next morning to test it. She guessed it would need at least that long. But she awoke early on Sunday, unable to wait any longer, and started repeating the work she had done the day before.

She started by pacing off her dorm room again and was relieved to find it was the same to within her margin of error, but that was the last reassuring bit of information she would get. She had only first bothered to count the steps up from the Common Room to her dorm until last night. There didn't seem to be any need before. But now, she counted them again going back down, and found that if she'd counted correctly (and when didn't she?), the spiral staircase was two steps taller.

With a sinking feeling in her stomach, Hermione left through the portrait hole and began pacing off the east corridor, the one from Gryffindor Tower to Ravenclaw Tower. It was supposed to be one hundred seventy-two steps long. She had measured it three times yesterday; it was one hundred seventy-two steps long.

Today, it was one hundred sixty-six.

"Oh, you have got to be kidding me."

Well, that did it. She as well and truly through the looking-glass. Hogwarts Castle not only changed shape and size from floor to floor, but also from day to day. No map of the castle would ever be more accurate than about ten percent, because it wouldn't stay put like any sensible building, and she had a sneaking suspicion that her dorm room would eventually change, too, when she wasn't looking. She supposed she could try to measure the outer dimensions of the castle, but she doubted that would work any better.

The one good thing about it was that she wouldn't have to measure the place more accurately than ten percent either. She took a couple minutes to step off the corridor at her normal walking pace to figure out the conversion. That would easily be accurate enough, and it was about four times faster. Even so, it was with an exasperated sigh that she finally sat down in the Great Hall for breakfast.

It didn't help that she had barely started eating when a pair of redheads sat down on either side of her.

"We commend you, Miss Granger," they said in unison.

"Huh?" Hermione answered lamely.

"Your measurements of the castle," the one on her left said.

"You were quite right." the one on her right continued.

"The floors don't line up at all."

"Oh, yeah, that," she said in annoyance.

"We didn't think anyone knew the castle better than us, did we, George?"

"No, indeed, Fred. Not even Filch. How ever did you do it, Miss Granger?"

"I just asked a question that nobody else bothered with," Hermione said, hoping she could get rid of the two troublemakers quickly. "Everyone else said the castle kept changing, so they never tried—Unfortunately, they were right. The measurements were different this morning."

The twins stared at each other to digest this information.

"Learn something new every day, don't we?"

"It seems we do. So, if you don't mind our asking, how do you intend to complete your map?"

"Well, I guess I'll just have to draw it approximately. I don't have time to measure everything three times and take an average. It won't be an architectural drawing, but I'll at least be able to find my way around."

Fred and George grinned to hear that she would be keeping up her exploration efforts. "Well, best of luck to you then," Fred said.

"Please let us know if you make any more discoveries," George added.

"And if you should find yourself in need of a favour—"

"Such as if a certain Slytherin git needs a good pranking—"

"We would be delighted to assist you."

"Of course, we might do that anyway."

"Thanks, I'll…keep that in mind," she said nervously.

"Pleasure doing business with you," they replied together. Unfortunately for her, they stayed right where they were and got back to eating, but thankfully their brother, Ron, showed up and got them into a conversation about Quidditch. Hermione just tuned them out. She had some Transfiguration to finish and a letter home to worry about. She also wanted to finish some sketches she had started. She wasn't much of an artist, but geometrically defined architectural features she could handle. She decided she'd had enough of the exploring bit for one weekend.

Well, she did step off that east corridor on the seventh floor one more time that afternoon. Sure enough, it was about a foot and a half different. That meant that the corridors apparently changed smoothly over the course of the day rather than just overnight or at midnight or something. That was some good news. At least she wouldn't have to worry about the floors suddenly shifting under her feet. In some ways, it seemed like the castle was breathing. It would just be nice if it could breathe in Euclidean spacetime.

Dear Hermione,

Thank you so much for the sketches of your dorm room and common room. It looks like you have a very nice place to live. Be sure to send us some of the rest of the castle when you get the time. That sounds pretty strange about the castle having non-Euclidean geometry. Your father didn't think even magic could do that. He says to try not to fall into any obtuse angles.

We're very glad you've found a good study group and got to know some of your classmates. We were worried your letters would wind up being all about classes. If you've found some people who are really willing to share the work like that, be sure to stick with them. Friends like that are hard to find. That Harry Potter boy sounds nice, too, and he was raised in our world, so you have something in common.

About Professor Snape, it sounds like he's a pretty lousy teacher from what you wrote us. He shouldn't be allowed to behave like that. In our world, he would be sacked if he was like that all the time, even if he had tenure. Unfortunately, we don't think there's much we can do to help. The magical world seems to be pretty self-contained. The best chance you have is to talk to Professor McGonagall, and if she won't do anything, Professor Dumbledore. In the meantime, just keep trying your best. It sounds like you're learning the subject better than the book taught it, at least, and doing well enough that he has to give you a good grade, so you should be okay for now.

Keep up the good work, and stay out of trouble.

Love,

Mum and Dad

She settled into her routine better in the second week. The classes were challenging in ways she had never imagined either school or magic could be, but she was doing well in them. She could find her way to all her classes now, too, though that in no way reduced her desire to map out the rest of the castle.

But she groaned when she saw the notice posted in the Gryffindor Common Room that night: Flying Lessons start on Thursday…with the Slytherins. Hermione was not athletic or even all that coordinated. She could calculate angles in her head faster than anyone, but that never seemed to translate into prowess with a tennis racket or a billiards cue. And doing anything athletic in the air would only make things worse. She was okay on a bicycle, but roller coasters always made her a bit queasy, and those even had seat belts.

She made a beeline for the library before curfew and found a book called Quidditch Through the Ages. She skimmed over the bulk of the material on Quidditch itself (not the best-designed game, she thought) and focused on a rather well-written section containing basic flying tips. With a few exceptions, most kids who were raised in the magical world had been on a broom at least a couple times, so Hermione had some catching up to do. On Thursday morning, she shared the tips she had learnt with Sally-Anne and Neville Longbottom, both of whom had also never been on a broom. Neville was even more frightened of flying than she was—unsurprisingly, given his unfortunate clumsiness. However, everyone else at the table seemed to be tuning her out.

Madam Hooch, Hermione saw as they lined up that afternoon, had yellow eyes like a hawk. That was not a normal human eye colour, and she wondered if Madam Hooch also had some non-human blood in her. Or maybe it was just magic.

She supposed it was a nice day for flying, but not knowing how to fly and having to learn with the Slytherins really put a damper on her spirits. The state of the brooms didn't help, either. Hermione had seen photographs and illustrations of broomsticks in Quidditch Through the Ages and looked at the school brooms with dismay. She had heard the Weasley Twins complain about how these brooms never flew straight, and she wasn't surprised. The school brooms weren't even standardised. There were forty-year-old Cleansweeps and Comets, Shooting Stars, and some that were clearly off-brands. They all had bent twigs and scratched handles, neither of which boded well for their performance, but she supposed they would be safe enough for the low-intensity lessons they would be having—almost like training wheels, she thought.

"Stick out your right hand over your broom," called Madam Hooch at the front, "and say 'Up!'"

"UP!" everyone shouted.

Hermione's broom twitched and rolled over. On her left, Neville's hadn't moved at all, but on her right, Harry Potter's broom leapt directly into his hand, as had a couple of others, including Draco Malfoy's. Evidently, most magical children didn't learn that part of broom handling early.

Hermione was sure she could do better than that. This was like casting a spell, wasn't it? Except the broom had a rather more limited repertoire than a wand. She focused on the feeling of flowing energy that she always felt with her wand and tried to reach out to the broom with it.

"UP!" she shouted again. The broom leapt off the ground, though she had to scramble to catch it. Most of the students got their brooms to rise after a few tries, but Neville had to pick his up by hand.

"Now," said Madam Hooch, "hold your broom up on your right, like so, and put your right leg over it—near the back, right in front of the bristles. You'll be able to feel the Cushioning Charm. Don't sit any farther forward, or you'll slide off the end."

That made sense, Hermione thought. It was just like mounting a bicycle. The Cushioning Charm even felt like a bicycle seat. And she could tell at once that its position just in front of the bristles was at the broom's centre of gravity—the only place one would be able to stay balanced on it.

"Good, good," Madam Hooch continued. "Grip the middle of the handle, right hand in front, thumbs pointed down—no, Mr. Malfoy, thumbs pointed down."

"Madam Hooch, I've been riding a broom for years—"

"Then you've been riding it wrong for years. Thumbs pointed down," she repeated. Some of the others snickered at the arrogant boy.

Hermione twisted her wrists to point her thumbs toward the ground. Her first instinct had been to hold the broom with her thumbs on top of the handle, like Malfoy did, but she immediately realised that the correct grip gave her better control of where the broom was pointed and would help her to lean with it. It was little uncomfortable having to lean forward to hold it properly, but broomsticks at least didn't seem like a completely unreasonable way to fly anymore.

"Now, when I blow my whistle, you kick off from the ground, hard," said Madam Hooch. "Keep your brooms steady, rise a few feet, and then come straight back down by leaning forward slightly. On my whistle—three—two—"

And that's where the sensible part of the lesson ended. Neville was far too jumpy and kicked off the ground before the whistle, shooting up in the air and then falling off his broom and falling to the ground with a horrific thud. Hermione sighed with relief when Madam Hooch said he only had a broken wrist. She was sure it would have been worse after seeing that fall. She had heard before of people falling from high buildings and bridges and walking away when they shouldn't have—when they should have died, even—but they were the rare exception. Oddly, many of those people tended to be drunk. Perhaps it was that they couldn't brace themselves properly in that state and just let their limbs absorb the impact. She also knew that witches and wizards were built a bit tougher than muggles, but even so, Neville was extremely lucky to walk away from that landing.

And then that awful git Malfoy and his goons had to go and make fun of him and take his gift from his grandmother. Honestly, what kind of people thought falling three stories and breaking a wrist was funny for anyone?

But that was just the start. Harry decided he didn't like Malfoy's behaviour either, which quickly escalated into an airborne dogfight between the two boys, not five minutes after Madam Hooch specifically told them all to stay on the ground, which ended with Harry very nearly crashing and possibly dying in order to catch Neville's Remembrall, after which Professor McGonagall stormed out and dragged Harry into the castle.

Hermione stood frozen in terror when it was over, her hands trembling, unable to speak. Raised by muggles or not, that was still the famous Boy-Who-Lived who had just very nearly died and was now sure to be expelled from Hogwarts—and rather deserved it, for that matter. Just what kind of place was the magical world after all? Malfoy, Crabbe, and Goyle looked triumphant, smugly lording their victory over the Gryffindors. A couple of the Slytherins looked uneasy about this development, but most of them went along with the trio.

The Gryffindors got the last laugh, though, when Madam Hooch came back out, glaring at Malfoy. She benched him for the rest of the lesson, gave him a detention, and took ten points from Slytherin. Hermione was a little disappointed that he wasn't out of Hogwarts faster than he could say "Quidditch", as she had threatened, but it was still worth it to see the git wilt under those hawkish eyes.

"Now that's settled, we still have some time for the lesson," she told the rest of the class. When I blow my whistle, kick off from the ground, hard. Hover at a few feet, and then lean forward slightly to descend. Ready? Three—two—one—"

Madam Hooch blew her whistle, and Hermione kicked off the ground and rose into the air. She was wobbly, like when she'd first learnt to ride a bike, but she was hovering successfully. Some of the others laughed or whooped with joy to be in the air, but she was less enthusiastic. When she nervously tilted the handle forward, the broom gently settled back down to the ground.

Madam Hooch led them through the basics of manoeuvring: speed up, slow down, left, right, up, and down, all at very low speeds. Hermione was competent, despite the substandard broom, but she knew she would never be able to match the native skill Harry had shown. Indeed, most the class could fly circles around her. She would be happy if she could just share their joy at flying with the birds by the end of the semester.

Hermione wasn't sure whether to be relieved or angry when she saw Harry was still there at dinner, but when she learnt from the whispered rumours that he had been made Seeker on the house Quidditch team, she decided to go with angry. How could that boy break the rules so blatantly and be rewarded for it? A part of her wanted to blame his fame, but she'd seen well enough that Harry Potter didn't really care about his fame, and, apparently, he really was that good at flying.

And then, of course, Malfoy had to come around and get in a few more digs at him. Hermione honestly wasn't sure who to be angrier with as she watched the pair from the corner of her eye over her dinner as Malfoy challenged Harry to an after-hours duel, and Ron accepted for him. Trust a Weasley to make things worse. Harry had barely got out of being expelled once today. Now he was going to try and break curfew, too?

She tried to talk Harry out of the whole thing after Malfoy left. Unfortunately, her argument that he would lose Gryffindor a bunch of points probably wasn't her most persuasive one, but she couldn't think of any better hold to use on the pair just now. A duel would be dangerous, of course, and she suspected Malfoy knew more curses than Ron and Harry put together—could probably cast more curses than Hermione herself, if the rumours were true, but after seeing Harry risk his life on that broom, she didn't think that would convince him any better. And it seemed he just couldn't resist showing up Malfoy.

Well, there was more than one way to handle this, though. She loaded up on her homework that evening and stayed up late in the Common Room, resolving to work until midnight so she could stop those two before they caused any trouble. She strongly considered telling Percy, who seemed to be the lone responsible brother in the Weasley family, but going the tattle-tale route wouldn't win her any favours, and she felt like she would be on thin ice with Fred and George if she stepped too far out of whatever passed for their line.

Well, that hadn't been her best idea.

Trying to stop Harry and Ron leaving had only served to get herself locked out of the Tower with them. The Fat Lady must have gone visiting, which she would have admitted was completely within her rights since no one was supposed to be out in the corridors at this hour, but at the moment, she was preoccupied with more pressing matters.

Like the fact that she was locked out of Gryffindor Tower.

After curfew!

With a couple of self-centred idiots!

(And Neville, who had forgotten the password.)

With Filch chasing them!

With no other recourse, she had followed the boys to the Trophy Room. After all, they were the closest thing she had to an alibi: the only reason she was out after curfew was because she was trying to stop them. They had made there without incident, but Malfoy and Crabbe weren't there yet—and didn't show up by what Hermione was sure was well past midnight. Of course she realised, it was an obvious trap to get Harry in trouble (which she should have seen from the start), and that was when Filch had shown up.

From there, one thing led to another, running down one corridor and then another and then a hidden passage that let out onto an open air bridge that she hadn't had cause to use before, then into the corridors of the West Wing into Peeves, the poltergeist, and then down yet another corridor—straight into a locked door.

Ron was sure this was the end. (Gee, where was that attitude earlier?) But Hermione wasn't panicking quite yet, though. She was pretty sure from the whispers of the older students that most of the locked doors in the castle would open with a simple Unlocking Charm like the one the rest of the class would catch up with in the spring. At this point she'd take breaking another rule or two to keep out of Filch's clutches. (God, what was happening to her?) But, no, she'd forgotten her wand in the tower! How could she get in now?

Wait a minute—Harry was coming here for a duel, wasn't he? Using someone else's wand was tricky, but if she could put enough power through it—

"Oh, move over," Hermione snarled. She grabbed Harry's wand, tapped the lock, and whispered, "Alohomora!"

The lock clicked and the door swung open—they piled through it, shut it quickly, and pressed their ears against it, listening.

But Hermione didn't hear what was being said. She didn't hear anything just now, since she saw movement in the corner of her eye, and when she turned to look, she promptly froze stiff.

She'd got turned around with all that running. (Oh, why hadn't she spent more time on her map?) But when she looked now, she instantly knew where they were, and why no one had been using the Stone Bridge on the third floor.

They were in the forbidden third floor corridor. The one that contained "a very painful death", and Hermione knew now that Dumbledore hadn't been exaggerating.

There was a dog in the corridor.

It was ten feet tall.

It had three heads.

It had three heads!

The sight of those three heads would haunt her dreams forever if she lived through this: three pairs of rolling, mad eyes; three noses, twitching and quivering in their direction; three drooling mouths, saliva hanging in slippery ropes from yellowish fangs.

The dog came to its senses upon seeing them in its corridor and started growling at them. They were all going to die, she thought. They were at the gates of the Underworld—it was right through that trap door under the feet of Cerberus, the dreaded hell-hound of Hades—and they were all going to die.

And then—thank Zeus or Jehovah or Merlin or whoever, she didn't much care right now—she fell backwards.

Harry had opened the door.

They ran again, not even looking to see if Filch was chasing them. They ran and didn't stop, even while climbing up four flights of stairs, until they reached the portrait of the Fat Lady and dove into the Gryffindor Common Room, where they lay on the couches and the floor a while until they could speak again.

"What do they think they're doing, keeping a thing like that locked up in a school?" said Ron finally. "If any dog needs exercise, that one does."

Could he really be that thick? Hermione wondered. She'd sunk into a mythology-fuelled hysteria, and she'd still spotted it right away. "You don't use your eyes, any of you, do you?" she snapped. "Didn't you see what it was standing on."

"The floor?" Harry suggested. "I wasn't looking at its feet; I was too busy with its heads."

"No, not the floor. It was standing on a trapdoor. It's obviously guarding something."

She stood up, glaring at them.

"I hope you're pleased with yourselves. We could all have been killed—or worse, expelled. Now, if you don't mind, I'm going to bed."

She trudged up the seven flights to her bedroom, not waiting around to see if any of the boys had any bright ideas about what the dog was guarding, or worse, going back to find out. While she could agree with Ron about the madness of keeping that monstrosity in a school, that was about the only intelligent thing that any of those three had said all night.

She was all the way into bed before it hit her: "Or worse, expelled?" she whispered. "Good Lord, I really am losing it!"