Joohyun carefully guided Seungwan out of the library, her light grip on the girl’s elbow ensuring that she didn’t run into any walls while her nose remained firmly buried in her Muggle Studies textbook. She made her way across the floor with Seungwan in tow, slowly at first and then gaining speed as she grew confident that the Hufflepuff could match her usual pace without tripping over her own feet.

“So position is constant in time, unless the object has velocity. And then it’s linear in time, with the slope corresponding to the velocity,” Seungwan mumbled, probably reading the sentences off of the page. “Fascinating. Muggles really do have formulas for everything.”

They made it down two empty corridors, Seungwan never pausing her mumbling except to study a particularly stubborn block of text with a small frown. Finally, they made it to a flight of stairs that seemed likely enough to lead them to the next floor, rather than land them in the dungeons or simply end in front of a completely door-less stretch of wall. Joohyun hopped on the first step before the stairway could change its mind, cautiously pulling Seungwan along, and found that the girl adapted easily enough, legs mechanically beginning to climb the steps.

“Now if you add acceleration,” Seungwan continued to read aloud, “it will be quadratic in time, so that the trajectory will be a parabola. Oh, that’s a nice picture. ‘Projectile motion,’” she enunciated the title of the graphic in question, a curved line drawn over a cartoonish depiction of a ball kicked upwards in exactly the fashion of a Muggle textbook. It had probably been taken from one, Joohyun mused as she studied it without much interest.

Now on the third floor, they made their way to the Charms corridor and then to the staircases waiting innocently across from it. These were much better behaved than the central ones, so that Joohyun needed only a quick glance to check they were up to no tricks before assuring herself that they were safe to use.

When they arrived on the fourth floor, Seungwan was muttering about circular motion. On the fifth floor, she was stuck on the differences between the centripetal and centrifugal forces, which Joohyun could have done nothing to clarify, even if she had managed to steal Seungwan’s attention away from the book that had so completely absorbed her that she hadn’t even noticed they were more than halfway up the castle.

On the sixth floor, Joohyun directed herself to the northernmost corridor, feeling along its length for the few loose bricks that concealed the secret passage they must now take to reach the Northern Tower. Once she’d found the entrance, she took out her wand and tapped the bricks in a careful incantation, putting it back in the pocket of her robes when the wall began to open up before her. Seungwan followed her into the relative darkness without a word of protest, only pausing to cast a quick Lumos so that she could continue her reading.

Joohyun always preferred taking this secret passage over the usual method of entering the Northern Tower at its base and climbing up the endless steps of its long spiral staircase. She could say it was because it was more practical, or less cramped. But really, she just liked that it was her own little secret, hidden from everyone else at school.

They traversed the dark pathway, their steps echoing along the narrow corridor. The passage was another of Hogwarts’s mysteries, a miracle of architecture. Seen from the outside, there was no possible way to connect the Northern Tower to the sixth floor of the main building, and yet here they were. Travelling through some impossible space, suspended in implausibility.

A moment after leaving the tunnel, it would be impossible for a casual observer to find where they’d come from, the wall behind them back to its usual, unsuspicious regularity. And there, only a few steps away, was Joohyun’s favourite balcony, tucked away in a corner of the roof.

“Is this really what carousels are like? Has the book got it wrong?” Seungwan asked dubiously, the sudden sound of her voice after a tentative silence coming as a surprise. “Muggles pay to get on something that just spins around until they’re dizzy?”

“They don’t move fast enough to make you dizzy, usually,” Joohyun finally spoke up. “And they’re for children.”

Seungwan nodded along, seemingly paying attention. It would be the first time since they’d been in the library. Since around the time Joohyun had grown bored of studying when they weren’t even reviewing the same subjects, a bit before she’d slowly packed away her things, then Seungwan’s things, then stood up and pulled Seungwan away from the gloomy room.

“Oh, that makes much more sense. The book made it sound like grown Muggles were paying just to make themselves dizzy.”

Seungwan’s face was still buried in the pages of her textbook, so she missed the amused smile that tilted Joohyun’s lips as she considered that, in reality, the book wasn’t too far off.

“They do, actually. Just not in carousels. The ones that make you dizzy are called roller coasters.”

“Those are in here too!” Seungwan sounded far too excited for someone reading a Muggle Studies manual. “I think they might have gotten a few of the names mixed up,” she added, squinting as she ran her eyes over the page once more.

A sudden thought seemed to cross Seungwan’s head and fell slightly open, lips curved into an excited smile. She finally ripped her gaze from her book, turning it towards Joohyun instead.

“Have you ever been to an am-“ was all she managed before she finally registered her surroundings. Her question spluttered away into silence as her eyes widened, pupils darting to one side and then the other. “Where… are we?”

“Northern Tower,” Joohyun replied, unbothered.

“And, um, how did we get here?” Seungwan inquired further, eyes still roaming around the vast empty space around them, so different from the silent and empty library that she’d probably expected to see.

“The usual way? We walked up the stairs. Do you really remember nothing?”

Now Joohyun couldn’t keep the amusement from her voice, but she found that it tended to ease some of Seungwan’s instinctive nerves, or at least divert them towards the most ineffectual form of indignation she’d ever encountered, so she wasn’t too bothered by the slip.

“Right. The stairs. I remember stairs,” Seungwan slowly mused. She nodded to herself, the gears clearly turning in her head. “Did I cast a spell, for some reason?” she asked dubiously.

“Not that I can recall,” Joohyun lied smoothly. If Seungwan didn’t remember the secret passage, she might as well keep it to herself. The fewer people who knew about it, the better.

Seungwan took the denial in stride, only shrugging off the vague memory. She turned to the unobstructed view of the school grounds, showing everything from the Black Lake to the Quidditch pitch, then returned her attention to Joohyun, a sheepish look on her face.

“So, that view is lovely. Really lovely. It’s- You can really see everything from up here,” she began diplomatically. Joohyun nodded in agreement, but didn’t bother saying anything. “I just… don’t… Why did we…?”

The silence stretched between them as Joohyun waited for Seungwan to finish her question and the Hufflepuff merely looked at her in clear discomfort. They hadn’t quite made it past Seungwan’s fear of Joohyun, although it did stray from her mind now and again. They’d get there.

“When I’m tired of studying, I come up here to relax. I wanted to take a break.” As soon as the words were out of , Joohyun could see Seungwan’s face falling, worry filling her eyes. “I brought you along because you could use the fresh air. If you want, I’ll leave you in the dusty old library next time.”

She wasn’t going to make it any clearer, but hopefully that would be enough to relieve Seungwan’s ridiculous guilt. Like she was forcing Joohyun to study with her, somehow.

Seungwan said nothing. She gazed at the landscape spread out before them once more, then lowered herself to the ground and leaned against the wall, opening her book in her lap. Satisfied, Joohyun sat down next to her, eyes firmly on the grey sky overhead.

She’d be happy to simply sit there, wordlessly, following the lazy movements of the clouds across the endless horizon while Seungwan studied whichever nonsense was next on the program for Muggle Studies. But slowly, from the corner of her eye, she became aware that Seungwan was lingering longer and longer on each page, her gaze flickering away from the book more and more often.

At first, Joohyun thought that she was just tired of studying, but then she noticed that Seungwan was actually looking at her. Short, nervous glances that immediately shifted away only to return a moment later. She let her attention fall away from the sky entirely, studying Seungwan more attentively only to realize that every time her eyes returned to Joohyun, she seemed to take in a breath, as if to say something, before letting it out in a quick sigh of surrender.

She was like a child, really.

In one swift motion, Joohyun reached over and pulled away Seungwan’s book. It was safely tucked away by her side, where the Hufflepuff couldn’t possibly reach it, before she could even react.

“You want to say something,” Joohyun said in lieu of explanation. Seungwan blinked at her, confused but not denying it.

“It’s… It doesn’t matter. I had a question, but it’s nothing, just a dumb thing. May I please have my book back?” Seungwan requested, not sounding all that interesting in recovering it.

“Ask.”

Seungwan looked all around as if gathering her strength, then her eyes settled on Joohyun with an unusual glint. “Have you ever been to an amusement park?” she asked in a flurry of words.

Joohyun couldn’t help but quirk an eyebrow at the enthusiasm, corners of her lips almost twisting upwards without her permission. “Yes. I went with Seulgi a couple of times.”

“Did you go on the rides?” Embarrassment temporarily forgotten, Seungwan forged ahead excitedly.

“A few. I’m not the biggest fan of paying to get dizzy.” Or heights, but that didn’t need to be shared.

Seungwan nodded, mouth half open. “How was it?”

“It was… Muggles have strange ways to entertain themselves. It’s interesting. They came up with all these inventions to work around not having magic. Electricity and,” she waved at the abandoned book, “physics, all these formulas. And then they apply them to things like roller coasters. They’re so creative, in the most unexpected ways.”

“Did you do a lot of Muggle things with Seulgi? You know so much about them,” Seungwan added, and she seemed in awe more than anything else.

“Well, Seulgi lives in a Muggle town, so I suppose so. All the usual wizard pastimes weren’t available.”

There was a small smile on Seungwan’s face, almost wistful, as she took in Joohyun’s words. “You spent every summer together, didn’t you?”

“Some of it, anyway.”

“You must have had a lot of fun together. Even if you couldn’t do wizard things.”

“It was alright. It was… summer.”

Joohyun shrugged, feeling like the words were self-evident. They’d had day after day to entertain themselves as they pleased, flying on brooms in the protection of their backyard or exploring the small town, watching television or playing catch, dragging Yerim along on their adventures or joining her make-believe games. Just summer.

“Did you ride a bicycle?” Seungwan carried on. Joohyun nodded, a little taken aback at her enduring interest in the topic. “I always wanted to ride a bicycle.”

“Seulgi invited you to visit, didn’t she?”

It suddenly sprang to Joohyun’s mind, how Seulgi had asked Seungwan, not just once or twice but every single year. She’d never accepted the invitation, and Joohyun had always more or less assumed that it was because Seungwan knew she’d be there and would rather avoid the entire situation. The thought that she’d been the obstacle between Seungwan and a Muggle summer with Seulgi had never made her feel all that guilty, until this moment.

“Oh.” Seungwan seemed almost surprised by Joohyun’s remark. “Yes, she did. A few times. But it was always, uh, bad timing. It was hard to fit the trip in my summer program,” she added with an apologetic shrug, not really elaborating.

“Summer program?” Whatever it was, it appeared that Seungwan’s rejection of Seulgi’s invitation hadn’t had anything to do with Joohyun after all. It was… a relief?

“Oh, that’s just- My parents usually plan some activities for me over the summer. To make sure I don’t waste it away,” Seungwan added with a chuckle. “You know, some kind of physical activity, tutoring, etiquette and dancing lessons. Not to mention all the events at the house; it would be hard to explain that I’d missed my great-aunt’s birthday luncheon because I was at a Muggle town riding a bicycle.”

Was that her summer? Her whole summer? Suddenly, Joohyun and Seulgi’s silly races to the ice cream shop seemed so much more precious. Even those impossibly warm afternoons, when Mr. Kang would get off work early and fill their small inflatable pool in a shady part of the garden. Joohyun would dip her feet in, the water barely reaching her knees, and then Yerim would rush in and splash everything in their vicinity, drenching Joohyun’s summer dress and Seulgi’s overalls.

“It’s a shame, though,” Seungwan commented lightly, pulling Joohyun away from her thoughts. The Hufflepuff’s finger drew aimless patterns on the corner of her robe, moving absently. “It sounds like it might have been fun.”

She smiled at Joohyun, her usual smile, apologetic and reassuring. The sun broke through the cover of clouds, casting the entire balcony in light, and for once, Seungwan’s smile didn’t seem all that convincing.

“Yeah. It might have been.”

(…)

Joohyun sighed, looking up from her Divination notes. Studying with Seungwan was usually better than the lonely alternative, despite the girl’s tendency to mutter to herself as she took in particularly challenging material, but right now she was growing increasingly distracted by Seungwan’s fidgeting.

It had been going on for about half an hour. Seungwan would press her lips tightly together, release them with an impatient exhale, then lift her head as her eyes swept the common room from one end to the other before returning her attention to the page in front of her, all the while twisting her quill between jittery fingers.

Every once in a while, she would tentatively bring quill to parchment and sketch out a sentence that quickly petered out into nothing. Then, frozen right hand resting on the desk, her left would dig into her own hair and run through it carelessly, tugging as if to force a spark of inspiration out of her brain.

Joohyun watched the way the shoulder-length locks became messy and tangled, ink beginning to stain their tips from Seungwan’s careless handling of the quill.

“You’ll go bald if you keep pulling your hair out like that,” she commented tonelessly. Seungwan started in her chair, like she’d forgotten about her presence. Instead of answering, the girl only looked down in embarrassment and tentatively brushed her hair back into place.

“What’s so terrible, then?” At Seungwan’s confusion, Joohyun nodded towards her notes, which hadn’t yet progressed beyond a few half-desperate scribbles.

“Oh. It’s just Arithmancy.” Right. Made sense. Joohyun nodded solemnly, needing no further explanation, but Seungwan carried on. “We have a project for the break, a thought experiment of sorts. We have to think about the effects of simpler and more complex mathematical operations on the intrinsic properties of numbers.”

“Hmm. Sounds dreadful.”

Seungwan sank back in her chair, lower lip trapped between her teeth and hand ready to return to its fruitless scribbling, but Joohyun wasn’t quite ready to drop the subject. “And there’s nothing about it in your textbook? Maybe we should go to the library, there must be something useful there.”

“No, the professor said we shouldn’t consult any books for the assignment.”

“And you’re being graded on it?” Joohyun exclaimed more than asked, indignation flaring at the ridiculous imposition. “That’s completely ridiculous!”

“No, no, it isn’t graded!” Seungwan quickly cut in, hands raised as if trying to wave away all of Joohyun’s misdirected anger. “Like I said, it’s just a thought experiment. We’ll discuss it in class after the break.”

“It… isn’t graded,” Joohyun repeated slowly. And she didn’t mean to judge, not entirely, but she couldn’t keep her eyebrows from raising and her voice from hinting at her disbelief. It was just hard to wrap her head around the fact that, out of everything that Seungwan had to prepare and study, this was what she was devoting her time and sanity to. A thought experiment that wouldn’t even be graded.

“Well, this isn’t,” Seungwan pointed out miserably. Her gaze fell on her nearly-empty parchment, staring so intensely that it seemed like it might burst into flames on the spot. “But if I can’t do it, what else can’t I do? If I can’t even work my way through a simple discussion question, what will the actual NEWT be like?”

As she spoke, her eyes grew wider and brighter, and once again Joohyun feared that Seungwan might finally crack right when there was nobody around but herself to deal with it. She watched as the Hufflepuff blinked away her tears, panic still clear on every feature but carefully restrained.

“Alright, well… Isn’t Ahn Hyojin taking Arithmancy as well? Can’t you talk about it with her? Discuss it together before class,” Joohyun offered reasonably.

Unlike what she’d expected, Seungwan’s distress didn’t seem to ease at all with the suggestion. Instead, the girl only slumped back in her chair, nervous panic slowly being replaced by hopeless lethargy.

“And admit that I can’t do it without help,” she said, barely a hint of emotion in her voice.

“A Hufflepuff? Refusing help?”

The mood was probably not right for the joke, especially considering Seungwan’s issues with all that being a Hufflepuff entailed, but it had been the first thing to pop into Joohyun’s head and then it had been out in the world before she could prevent it.

“I’m still my parents’ daughter,” Seungwan said softly, and suddenly it was all a bit too much. Joohyun couldn’t imagine how it wouldn’t be too much for Seungwan as well.

Straight Os on her OWLs. More NEWTs than Joohyun could count on both hands. Summers spent with tutors and teachers and endless schedules, friends’ invitations cancelled, never anything nice. No riding bicycles or eating ice cream or going to amusement parks. Never anything fun.

She surged to her feet, work abandoned without a second glance as she made a split-second decision.

“Come on!” she demanded of the girl across from her, who only studied her quizzically.

“What?”

“Get up, we have to go!” She nodded towards the door, then stepped closer to Seungwan, ready to bring her along.

“What? Where?” The girl sat frozen in place, head whizzing between Joohyun and the exit, appearing unable to connect the dots.

“Just get up, come on.”

One step closer and Joohyun was tugging at her arm, slowly pulling her to her feet. Seungwan didn’t struggle against her, but her hands fluttered to her things, attempting to snatch them from the table.

Joohyun’s hand found them first and kept them there firmly. “No work.”

“Joohyun, I have to,” Seungwan cut in worriedly, then froze as if unsure that she was allowed a flat-out refusal. hung slightly open, wide eyes fixed on Joohyun’s, but she said nothing else.

Joohyun reined back some of the fire in her motions, tried to get her eyes to communicate anything beyond the impatient assertiveness she usually fell back on with the Hufflepuff. Her grip on Seungwan’s arm loosened then withdrew completely, and then they were just standing there.

“Just trust me, will you?” she finally breathed out, and it seemed far too exposed, so she quickly raised an eyebrow in expectation, resisting the urge to cross her arms.

Seungwan threw one last longing glance at her notes, then she relented with an almost imperceptible shrug, following along as Joohyun her heel and strode towards the door. Both girls were silent on their way through the corridors of the dungeon and up the stairs to the ground floor, where the large empty foyer sat silent and still. Flames flickered along the walls and Joohyun noticed with satisfaction that it didn’t seem to be snowing outside.

“Are we going outside?” Seungwan asked dubiously, and Joohyun didn’t bother with an answer when her steps took them in a clear enough path. Soon, they were by the wide open doors, which Joohyun crossed quickly. “Wait, I don’t even have my coat!”

“There’s your coat,” she replied simply, waving her wand in the familiar pattern as comforting warmth spread over both of their frames, like slipping under a thick down blanket.

She stepped into the Hogwarts Grounds, as deserted as the interior of the castle but, unlike it, filled with the sounds of whispering branches and shivering leaves, the grinding of gravel underneath her feet and the whistling of the wind around her ears.

They walked wordlessly, Seungwan growing more puzzled with every turn they took, until finally the Quidditch Pitch rose to meet them. Though the girl said nothing, Joohyun could almost hear the questions eager to rush past her lips as they walked around the structure to the storage shed that stood in its shadow, a rusty and desolate thing.

It was locked, of course, but one of the benefits of being a seventh-year taking NEWT Charms was the knowledge of several unlocking charms, far more advanced than the simple Alohomora. She tried them one by one until the magically-reinforced padlock popped open and she was able to reveal the contents of the small shed.

“Are those brooms?” Seungwan finally allowed herself to ask, peeking over Joohyun’s shoulder. “What are we going to do with brooms?”

Out of all the questions to ask, she’d certainly picked the most pointless one.

“Fly, of course,” Joohyun said, already stepping inside. She rummaged through the poor selection available, trying to find a specimen that wouldn’t pull to the side too drastically. “Any preference?”

“Keeping my feet on the ground?” Seungwan offered meekly.

“Nimbus it is.”

Grabbing a pair of passable candidates, she handed one to Seungwan and hooked a leg around her own, kicking off of the ground without hesitation. She floated a bit above the Hufflepuff’s head for a moment, then headed straight for the pitch, deciding against further encouragement. At some point, this had to be Seungwan’s choice.

Joohyun was already on her second lap around the field, following her usual trick of avoiding any glances towards the ground, when Seungwan appeared near the stands, broom held uselessly in her right hand. She was looking up at the Slytherin, too far down for Joohyun to read her expression. She watched as Joohyun spun through the air, her movements clumsy and her flight far from controlled.

Joohyun dipped down, eyes firmly shut to keep the vertigo from turning into panic, then back up in a manoeuvre that would have seemed beyond sub-par to someone like Seulgi. And when she reached the top of her wide arc and the wind blew all her hair back, beating against her face with harsh resistance, she could no longer hold in the laughter that bubbled up inside her. All around her was just sky, endless sky.

She laughed freely, spinning yet again and nearly losing her grip on the polished wood. When her face turned to the ground once more, she was smiling widely, her arms trembling but her heart racing with excitement.

Down below, Seungwan’s eyes locked with hers. And she must have seen it, because she swung her leg around her broom. She pushed off of the ground. She flew into the air, graceless and listing to the left, and on her face was the beginning of a smile.