clxxxviii. one time in arithmancy

"That's them, isn't it?"

"Those three there? No! Really? I wouldn't have guessed."

"Really! They don't seem that impressive, do they?"

"Are you sure they're the ones who beat out Crowle and Dread in the competition?"

"They beat out everyone. They're only fourth years!"

"Merlin."

Hermione pretended she couldn't hear Aron Lambkins and Cadence Coil's rather loud whispering as they passed the pair of older Slytherins in the hall. It had been the same everywhere she, Elara, and Harriet went for the past few days—furtive conservations and judging gazes, disbelief and curiosity in equal measure. Being in the common room was almost unbearable.

In retrospect, it hadn't been the best idea to so thoroughly thwart Slytherin's first trial. It hadn't occurred to Hermione to consider what the others would think when they finally stumbled into the Defense professor's classroom and found them there drinking tea with Slytherin, Harriet feigning sleep because Professor Slytherin would not stop staring. What had been a simple—perhaps even deceptive—move on their part, reading the Atlas, seemed a mysterious and astonishing feat to others.

As a result, Hermione and her two friends had spent the last two days as subjects of curiosity in their House. People speculated on how they'd performed better than seventh-year Iola Crowle, sixth-year Darren Dread, and the fifth-year prefect Mathilda Sterling. Hermione didn't have an answer for them. Neither did Harriet or Elara.

The worst scrutiny came from Accipto Lestrange, who expressed his interest with more malice than anything else. He had, as Professor Slytherin counted it, come in sixth place. Linden Craft came in fourth, though Hermione theorized he'd gotten tired of the forest and had abandoned the task for the comfort of the castle, inadvertently following them into the classroom some forty minutes later. In fifth came Desdemona Bragge, who didn't arrive at the castle before Lestrange, but who, according to Slytherin's Charmed invitation, managed to cover a much vaster area of the woods than poor, bitter Accipto. Lestrange had thrown a fit when he found out.

Hermione tried to understand Professor Slytherin's metric, but he hadn't chosen to disclose whatever guidelines governed his choices. In her opinion, it was all a farce; the wizard had his eye on certain students, and he'd game the system to ensure they made it as far as he saw fit. The first trial had been designed to make the overly-confident stumble and the under-prepared fail. Slytherin would have assumed Harriet, Elara, and Hermione would come together and be that much more likely to recognize and puzzle through his rouse.

Hermione was under no illusion that Professor Slytherin had any further use for herself or Elara beyond ensuring Harriet made it through to the final stages of his little social experiment. Hermione was a Muggle-born, free-thinking, and a woman. The latter might not factor too much in Professor Slytherin's recruitment, but it didn't play in her favor. Elara may have the pedigree and familial connections he preferred—but she was difficult. Complicated. Obstinate. She didn't have the…right temperament.

Harriet, on the other hand, was the orphan of an old Noble House, brilliant in Defense, and impressionable—as far as Professor Slytherin knew. He wouldn't find her easy to sway in the long run. Her morals and ideals were more fixed than anyone else's, but Harriet could lie and pretend if needed. She could smile, call him sir, and all the while despise the wizard for his connection to her family's death.

Hermione chewed on her lower lip and stared daggers at the floor. They waited by the door to Arithmancy for Professor Vector's arrival.

"If you're trying to set that stone on fire, there are better ways to go about it."

Blinking, Hermione raised her eyes to Harriet's. "I don't know what you're talking about."

"Mhm." Harriet readjusted her spectacles and craned her head to peer down the corridor. "Boot's coming."

Hermione didn't turn around. She didn't—but she may have peered more intently from the corner of her eyes than she usually did. Terry came to stand next to her a moment or so later, one hand on the strap of his school bag, the other casually tucked into his trouser pocket.

"Hi, Hermione," he said, smiling. "Black, Potter."

"Hello, Boot."

The grin on Elara's face was far too smug and knowing. Hermione scowled at her before addressing Terry. "Hello! How are you?"

"I'm good. Did you finish the assignment? I had to leave the last question blank."

"Oh, I got through it. We had to use the Chaldean method for that one."

Terry smacked his forehead. "I should have realized it. Let me guess; a lack of nines?"

Hermione chuckled. "Yes. It was cleverly hidden though, enough to make the Pythagorean method almost viable—."

Harriet let out a loud, bored groan. "Okay, I'm leaving."

"It's your fault for not taking the class. You would understand the fascination then," Hermione scolded.

"I don't want to take this class. Two plus two should always equal four, Hermione."

"It does! Usually. But, well—."

"Goodbye, Harriet," Elara interrupted before Hermione could go on a tangent about sequential reductions and Vibrational numbers. "Don't you have children to tutor?"

"You say that like we're not fourteen." Harriet stretched, arms above her head—a green snake tail visible in her shifting sleeve for a moment before it disappeared. "And no, I'm going to go hide so I don't have to listen to bloody questions about Slytherin's task. Ugh."

By then, Professor Vector came around the corner, carrying her usual bag bursting with scrolls and spare bits of parchment, threatening to come unraveled at the seams. The professor had proven her propensity before for dragging unwitting students into her classroom even if they weren't on her roster, so Harriet quickly fled in the other direction. Hermione straightened and followed Professor Vector into the classroom.

Terry leaned closer as they took their seats in the odd, rounded configuration facing the blackboard. Heat tinged Hermione's cheeks, and she told herself to stop being ridiculous right this moment.

"She seems a bit squiffy, isn't she?" he murmured in her ear, nodding toward Professor Vector. She noticed the professor had Charmed the lenses of her spectacles darker, and her graying hair looked as if it hadn't been washed.

"No," Hermione whispered back. "I think she's just tired." To herself, she added, and perhaps a touch hungover. Poor Professor Vector should watch her wine consumption while working on matrices so late at night.

"Either way, she's going to stick us with revisions today. Just watch."

Terry was correct, as Professor Vector did assign them revisions for the day's lesson as she slumped at her desk and made a valiant effort to remain awake. Hermione sighed and set her homework aside. She took out her textbook and opened it before her.

Really, she had too much going on to revise the same Arithmancy sequences again, and it seemed most of the class shared that sentiment as they retrieved homework for other classes or fell into quiet, muted conversations. Hermione's mind started ticking over the same thoughts it'd been considering in the hall—Harriet, Professor Slytherin, and the nasty web he weaved.

"So," Terry said as he glanced away from Professor Vector. "Would you hate me if I asked what happened with the trial all of you Slytherins have been whispering about?"

Hermione waved a hand in a half-hearted gesture. "They're being dramatic and silly. Nothing happened, really."

"Really?"

"Well. He set us the challenge of finding him, yes? But first, he led the group to the Forbidden Forest with the implication he would be hidden inside of it."

"Let me guess, he hid in his office instead?"

"Clever. Not many people guessed it."

"From an outside perspective, it sounds like something he'd do. He's not a straightforward bloke at all." Terry shrugged. "So, what happened? With you and Potter and Black? Did you pass his test?"

"Yes." Hermione squirmed in her seat. "We were perhaps slightly dishonest in how we went about it, however."

She slipped her Atlas out of her pocket and held it out for Terry to see. While she and her friends had decided to keep the Atlas a secret for the most part, Terry already knew of it. In fact, he'd helped Hermione muddle through some of its earliest Charms.

His brow rose. "Oh, I see. Has it been working well, then?"

"For the most part. It's still having the problem where the sheer amount of information stored makes it difficult for search commands that aren't readily apparent or specified. If they can't be specified, it'll heat until it shatters." Or sets something on fire again.

"Hmm." Terry leaned on his arm and turned his gaze toward the window, his face soft in the warm, early afternoon light. Hermione found herself fascinated by the dimple in his cheek until Elara—whom she'd quite forgotten sitting in the seat next to her—scoffed.

"Don't be difficult," Hermione hissed.

"Wouldn't dream of it." Elara reclined as much as the stiff desk chair would allow and flipped to the next page in her book. If Hermione wasn't mistaken, it was one of Harriet's Muggle fantasy novels.

Terry snapped his fingers, having had an epiphany, and Hermione whipped around to face him again. "What if you relayed the information through a probability sequence?" he said, eyes bright. "It would render decisions faster."

"If the Charms passed through a probability sequence every time we opened the Atlas, it would—."

"No, no. Not every time. What if you had it reckon the numbers as the information was input? The Vibrational numbers of dates, for example. Then Character, Heart, and Social numbers for people. If the Charms could be written to run those numbers through a probability sequence and then pull them through Pascal's Pyramid, the Atlas could better predict movement and information before it's written."

"The sheer amount of input would be hypothetically staggering," Hermione muttered, her mind working fast. "Critically so. It may only exacerbate the issue by needlessly compiling worthless data. But if I were to wrap the original circumdo ward in a second circumdo ward and write the equations directly into that…." Terry had potentially pointed out a means for the Argonaut's Atlas to not only sort information in a new fashion but to also predict specific trends—to detect the probability of behavior when people meet in certain places, at certain times, at certain dates. If Hermione could deduce a method to keep the reactive heat from building to intolerable levels as the Charms functioned—. "You're brilliant, do you know that?"

Terry flushed scarlet but looked very pleased with himself.

"Harriet would vomit to hear all this talk of arithmic rendering and probability," Elara commented.

"Well, she can vomit after she thanks Terry," Hermione said with a grin, dragging a fresh roll of parchment from her bag along with an inkwell and sharpened quill. "Enjoy your book. I have notes to take!"

It turned out to be a very productive period after all. Hermione wrote down what Terry suggested and quickly began scribbling in her own thoughts and questions underneath, jotting down books and pages she would need to reference in the future. Unlike Divinations, Arithmancy could be beautifully precise in its numbered sequences and relays—but it was also easily disruptable in a way Divinations, with all its nonsense static predictions, wasn't. She would have to fashion a way in which variables wouldn't quite literally blow the Atlas up in their faces.

Hermione did discover something…odd while she worked. Wanting to test how the map feature would react to newly imposed equations, she opened the Atlas to the image of the Great Hall, and as she flicked her wand over the glass and muttered spells, she glanced down to see the little dots crossing through. Given the hour, she'd expected the space to be mostly empty and it was, with a few exceptions.

One dot belonged to an Auror, Gawain Robards, and by his slow continuous motion, Hermione gathered he was on patrol. Another dot following not far behind was Barty Crouch, and she wondered what business could bring one of the Tournament judges to the castle.

Then, Hermione forgot all about Barty Crouch when she spied Rita Skeeter meandering about without a care in the world. She knew for a fact Skeeter and all other reporters had been banned from the grounds when a task wasn't in session, so what on earth was she doing prancing about the Great Hall in broad daylight? Why hadn't the Auror, Robards, done anything?

Something peculiar is going on.

Time passed quickly after that, and it seemed only minutes later that Professor Vector stood from her desk, mumbling in a daze, to dismiss them for lunch. Hermione returned the Atlas to its proper size and to its proper place in her pocket, rolling her notes up. Already prepared to leave, Terry capped her ink and handed it to her. A pink flush grew in his cheeks.

"So…are we still on to go to Hogsmeade next week?" he asked.

"What? Oh—yes, of course," Hermione replied, nearly crumpling her tidy parchment rolls when her hands spasmed. "I have a, um, appointment first. I have to get my dress robes for the Yule Ball."

Merlin! Hermione winced. I shouldn't have mentioned that. Oh no, what if he thinks I'm hinting at something? Am I hinting at something? Am I coming on too strong? Why isn't there a reliable book with answers for situations like this?!

"Err, speaking of the Yule Ball…." Terry scratched the back of his head and wouldn't meet Hermione's gaze. She had the sudden horrible premonition that he'd already asked someone to be his date—or some witch got the courage to ask him first. Oh, why hadn't she thought to do that? Who wouldn't want to go with Terry? He was smart and absolutely charming, with his lovely soft hair—.

"Hermione?"

And his smile. He was so kind and thoughtful—.

"Hermione?"

Startled, she blushed. "I—I'm sorry. I was distracted for a moment. What did you say?"

Behind her, Elara snorted into her gloved hand, and Hermione swore she'd hex the witch for bearing witness to her embarrassment once they were alone.

"I asked if—Black, do stop laughing, for Merlin's sake," Terry huffed, face red. "I asked if you'd like to go to the Yule Ball with me."

"Yes!" Hermione all but shouted. Then, in a quieter voice, "I mean—sure, of course. If you'd like. Because I would like. To go, that is. With you." She cleared her throat. "Yes, Terry, I would love to go to the Ball with you."

Before Terry could say anything else, something shattered from the next row over, and Hermione turned her head to see Draco half-bent over his satchel, his inkwell seeming to have slipped through nerveless fingers. He paid no mind to the sticky black mess seeping across the stones under his shoes as he stared at Hermione in horror.

She frowned. "Are you all right, Draco?"

Sputtering, he straightened and said, "You're going to the Yule Ball with him?"

What was he on about? Was it such a surprise Terry might want to ask her out? Because she wasn't beautiful? Or pure-blooded?

Hermione opened her mouth to give Draco a piece of her mind, but Elara already had him by the arm, pulling him off balance into her side.

"Come along, cousin. We'll be late for lunch. Apparently, you've already eaten some foot, but let's see if your appetite can be spared."

"But—."

Elara all but frog-marched him out to the corridor, forgetting the mess on the floor and one of Draco's unpacked textbooks. From the front of the classroom came Professor Vector's loud snoring as she slipped back into a heavy slumber.

Terry blinked as he looked from the door to Hermione. "You have bizarre friends."

"Yes," she sighed. "I do."

A/N:

Elara: "You and Krum should start a boyband."

Draco: "We should? Really?"

Elara: "Your first song can be 'She Doesn't Realize I Exist.'"

I had to learn how arithmancy works just to write this chapter. Will I ever use it again? Who knows, but it's trapped in my brain now.