The chaotic, rainbow swirl of the tunnel receded from Twilight's vision as she stumbled through the statue. Her feet – her human feet that she'd never grown fully accustomed to – caught on the pavement. She yelped and stumbled backward, landing on her bottom with an "oof." Panting, gasping, and rubbing her now-achy butt, Twilight looked around at the familiar sights of Canterlot High – the statue behind her, and the brick building in front. She'd made it.

Twilight rose to her feet and tore off, trying and succeeding by necessity to readjust to a human body on the fly. Sunset Shimmer's plea had been vague, curt, and barely qualified as a complete thought, but it was enough to make Twilight drop everything and run through the portal in the cold grip of panic.

"Something wrong," the message in the journal had read. "Come quickly."

Lacking context, her mind tried desperately to interpret Sunset's message. Frightening and improbable scenarios arose in her mind, only to be discarded once something new came up that topped it. She passed the minutes thus, frightened and trying desperately to ignore her burning, cramping muscles, until she arrived at the cozy, if not particularly stylish, two-storey apartment that Sunset Shimmer called home.

Twilight collided with the door and leaned upon it, pounding rapidly with hands kept curled into fists out of habit. "Sunset! Sunset!"

Or so she meant to say. What actually came out between gasps was a breathless "Sahhsaaah... Sahhsaaaaaah!"

The wood of the door wasn't particularly dense, and Twilight could hear Sunset's muffled voice on the other end. "That's her outside now – we'll see you in a little while, okay?"

Was she on the phone? How could Sunset be holding a conversation on the phone if she were in dire, mortal peril? Twilight continued her furious pounding, until the door unlatched and opened, and she fell forward into Sunset's arms.

"Wagh!"

"Twilight!" Sunset sounded concerned, though she looked, sounded, and for that matter felt no worse for wear. If anything, her concern was for Twilight, and no one else.

"Sheesh, look at you," Sunset said with an airy chuckle. "You've sweated through your shirt like a hundred times over."

"Ran... legs hurt... so does butt..." Twilight panted, gulping down lungfuls of slightly stale, recirculated air.

Sunset Shimmer herded Twilight inside and led her to a couch with faded purple upholstery, where Twilight gratefully collapsed. Sunset excused herself to the bathroom, leaving Twilight to look around and marinate for a while in her own sweat. The apartment was spartan, but well-kept, with inexpensive furniture, a dated-looking TV, an old coffee table with a pair of wine glasses and a bottle of something that looked pricey, but was probably cheap...

Which was an odd detail to find in the home of a minor, Twilight thought. Whatever happened to bowls of fruit, or flower vases?

Sunset returned with a wet towel and a waxy-surfaced paper cup of tap water. Twilight accepted them, rubbing her face down before greedily swallowing her drink, all while Sunset watched bemusedly.

"Did you sprint all the way here from school, or something?"

Twilight gulped down the last of her water, sighed with relief, and cleared her throat. "Had to. Got your message. Is everything... everyone... okay?"

A faint blush dusted Sunset's cheeks, and she turned away from Twilight. "Yeah, um... why don't you relax for a moment, and we can talk about it when you've caught your breath a little bit more?"

"Can't. Need explanation." She folded the soiled towel neatly, and placed it on the coffee table. "Did Apple Bloom set herself on fire?"

Sunset's head snapped back to face Twilight, and her eyes flew open incredulously. "What? No! Why Apple—"

"Was Flurry Heart kidnapped by evil hoteliers?"

"No one has been kidnapped, no one is on fire, and I'm pretty sure we don't even have a Flurry Heart in our—"

Twilight grabbed fistfuls of Sunset's blouse and pulled their faces together. "Human Tirek broke free from Human Tartarus and is rampaging through the greater metropolitan—"

"Okay, you need to slow down. Another mouthful like that, and I'm pretty sure you're going to pass out." Sunset dislodged Twilight's hands from her blouse and scooted away from her. "Deep breaths. Steady."

Twilight wanted to argue, but acquiesced – her vision was darker and blurrier than it should have been. So she leaned back and sank into the squishy couch, until her heartbeat slowed and her breathing steadied and she could talk without the risk of losing consciousness.

"Okay." Twilight let out a breath, sat straighter, and cleared her throat. "I'm good. Now. What is the problem? You sounded so freaked out in your message. Uncharacteristically non-grammatical, too."

There was a moment's hesitation on Sunset's part before she answered. "It's... probably better if I show you."

Sunset's apartment had a kitchenette adjacent to the living room, separated by a swinging door. She led Twilight to it, placed her hand on the door, and looked back warily.

"Brace yourself for this," she muttered. She gave the door a shove, holding it open with the length of her arm.

"Oh, come on. I've seen your kitchen before, Sunset; it can't possibly beaaaAAAAAAAAAAGH!" Twilight recoiled, clutching her limbs against her chest.

"Sunset! Who and what and how and why?!"

"All pertinent questions," said Sunset. "And I hope you'll help me answer them."

A gargantuan, perfectly spherical eyeball floated in the middle of the kitchen, a foot off the ground, with a pristine white surface, a vivid blue iris, and a pupil that dilated and constricted at an even rhythm. It fixed its monocular gaze on Twilight's own, and stared her down, silent, unblinking, and unmoving.

Twilight dared to uncurl a single finger from one of her tightly clenched fists and pointed it at the Eyeball. "That's... that's new, right?"

Sunset nodded. The Eyeball's iris pulsed and spun counterclockwise.

"Right. I thought so." Twilight swallowed. "Because I don't remember that being here last time I was over. It seems like the sort of thing I'd remember."

"Yeah, well..." Sunset released the door and let it swing closed, blocking the Eyeball from sight. "Didn't exactly see it coming myself when I rolled out of bed, so imagine how I felt when I saw it."

Twilight stepped up to the door, pushed it open slightly, and peeked through. The Eyeball swiveled in the air to meet her gaze through the crack in the door, and Twilight "yiped" softly, scrambling backward.

"Yeah, pretty much like that," said Sunset. She folded her arms, with one forearm sticking up and a thumb pressed against her chin. "I'm sorry for freaking you out with my message. I went a little nuts and my first instinct was to pick up the journal and write to you. Probably should have taken a moment to calm down before I did, but in my defense..."

She put her thumb between her front teeth and bit down gently.

"Yeah, no, don't worry about it." Twilight looked curiously at Sunset. "It hasn't done anything... like... sinister, has it?"

"No. Nothing yet. Nothing... intentional..."

Twilight frowned. "What do you mean by that? What did it do?"

"It, um..." Another blush, darker this time, colored Sunset's face, and she turned away from Twilight. "Do they say 'cockblock' in Equestria? It's a thing around here, but it's been so long since I've been home that I can't remember if they say it over there, too."

Twilight's eyes narrowed. "What."

"Oh, I guess they don't. It means—"

"I know what it means, Sunset!" Twilight fumed and stomped closer to her friend. "That's why you couldn't even manage two whole sentences of description? I was worried sick about you – about everyone! You could've been hurt for all I knew! Or dead! Or hurt and dying! Or something else just as awful!"

Sunset whirled around. "Hey, something awful did happen, alright? Do you know how long it's been since I've had a shot at getting with a guy? I was evil the last time I got laid, Twilight. That's how long!"

"That's..." Twilight stepped back, blinking. "More than I think I really needed to know, first of all. And second, that's not the point I'm contending here."

Sunset scoffed and brushed past Twilight, moving toward the couch to lean against an armrest and wrapping her arms around her midsection. "Look, it's... difficult, alright? Living the kind of life I do. Even when you've got the best friends in the world, you can get lonely – longing for the kind of intimacy that mere friendship can't provide."

"Sunset, that's sad and all, but I think you might be ignoring what I'm trying to say—"

"Sometimes that means you make a call to someone you know should be off-limits, and you invite him over for movies and cheap wine that you bought with your fake I.D. But sometimes, instead of watching that movie, you wind up re-opening old wounds and crossing lines, lines you drew in the sand to protect the both of you from each other. And from yourselves! From making mistakes that would just make life more complicated for the both of you! "

"...Why do you have a fake I.D.?"

"And maybe, sometimes, you step so far beyond those lines that you just know... there's no going back." Sunset bowed her head and shut her eyes, and Twilight could see the tears pooling between her lids, beading on her eyelashes.

"The die is cast. The Rubiclop is crossed. Your panties are... somewhere... you're not sure where; you lost track of them at some point amid all the groaning and groping and gyrating. Maybe it's the half-glass of wine you got through before you pounced on one another, or the lingering attraction drawing you together like two magnets that really, really want to screw. But one way or another, you find yourselves stumbling into the kitchen, a tangle of wet lips and roaming hands, grunting and gasping, desperate to form the two-backed beast of forbidden teenage love – or the right angle of forbidden teenage love, which was kind of the direction things were going."

Nervous sweat prickled Twilight's forehead. "Uh, do you need a moment? 'Cuz I'm starting to think I don't really need to be here for this."

"Because maybe you maneuvered him into the kitchen on purpose; maybe you've always wanted to get bent over the kitchen sink, because maybe you get thirsty sometimes during the act, and maybe nothing kills the mood faster than getting up for a swig of Gatorade mid-coitus, and having a water faucet three inches away from your panting mouth can be incredibly convenient, you know?"

Sunset opened her teary eyes and looked at Twilight, frowning slightly. "Or... I guess you wouldn't know about that."

Twilight's face burned. "Hey!"

"But," Sunset continued, irritation now simmering in her voice. "Before you can even get your proverbial foot in the door and forever change the nature of your post-relationship relationship with your ex-boyfriend, he spots an obscenely large cosmic eyeball where there shouldn't be one. Then he freaks out and starts babbling in terror, yanks his clothes back on, and—"

"Ex-boyf – seriously?" The bottle and glasses and their purpose came into sharp, horrible focus. "You tried to have sex with Flash?!"

Sunset's arms dropped to her sides. "Oh. Yeah, um. I guess I should have led up to that a little more smoothly."

"Sunset!"

"Well, if it's any consolation, I doubt he's ever going to be able to look at me again without thinking of today, alright?"

"You – I – he – that – ohhhh...!" Twilight stormed over to the couch, past Sunset, grabbed a throw-pillow, buried her face in it, and screamed a long, throat-rattling scream of exasperation.

When she was finished, and turned around to look at the nonplussed Sunset again, her face was calm. Her outrage was left behind on the pillow as a vaguely circular stain, the size of her mouth.

"Alright," Twilight said serenely. "We're getting off track here. Whatever reasons you may have had for calling me over here, and however..."

She inhaled, sharply and deeply.

"Annoyed I might be that you had your impeccably manicured hands all over my not-boyfriend... you were right to call me over."

Sunset smirked and stretched out her hand to regard her fingernails. "They are pretty nice, aren't they?"

"Anyway," Twilight said sharply. "Let's put all our other concerns aside for now, and just work this problem. Alright?"

Sunset shrugged. "Sounds good to me."

Awkward silence settled on the pair, as they gazed anywhere but at one another. Or at the kitchen.

"Incidentally," said Twilight. "How can you afford a place like this?"

The twin sounds of glass shattering and a car alarm triggering outside made Twilight jump. Sunset didn't seem fazed.

"That answer your question?" she said dryly.

To Twilight, there was nothing quite like an educational environment to melt away negativity, which Sunset probably knew when she brought her to Canterlot High. The classroom they were in was mostly undecorated, with bare blue walls and identical rows of desks – none of the personalized trappings that many of the other classrooms had, traces of the teachers who worked in them. The air hung heavy with the sharp tang of disinfectant, sweeter than any perfume, and the sterile white glow and subtle hum of the fluorescent lights lent a clinical air to her surroundings.

At the front of the room was a computer console built into a podium, and beside it, a polished black table, where Sunset sat beside a stack of science textbooks. Twilight ran her fingertip along the top row of buttons on the console's keyboard, and "qwerty" appeared on the computer's screen beside a blinking cursor.

Sunset watched her with a wry smile. "I've seen actual kids in actual candy stores who get less excited than you whenever you see a computer."

Twilight grinned sheepishly. "Sorry. It's just..."

"Nah, yeah, I get it. No judgment here." Sunset draped one leg over the other and leaned back, folding her hands over her top knee. "Revel in the splendor of human technological sophistication, my friend."

"I had a computer back when I lived in the library, you know, but it was nowhere near as sophisticated as this one. Puts every piece of machinery I own to shame." Twilight propped her elbows on the console and rested her cheeks in her palms. "I wish I could show this stuff to Starlight..."

Sunset's smile flipped into a frown at the mention of Twilight's student. Her back straightened, and she picked up a textbook, flipping open to a random page.

"Ah, yes. Her. And how is she doing with her studies?"

"Oh. Uh." Twilight forced a shaky smile. "Progressing. Naturally. Learning a lot about the magic of friendship. Every lesson learned is another step on the road to redemption, y'know. Heh."

Sunset's eyes flicked up at Twilight briefly, narrowed, then returned to the pages of her book. "Hmm. How lovely."

Twilight's face fell, and she mentally slapped herself – Sunset always got weird whenever the subject of Starlight Glimmer came up. She always figured it was just insecurity. Without cause, to be sure, but it was something she could sympathize with.

"I'm not replacing you with Starlight, Sunset." Twilight left the console and sat beside Sunset, the stack of textbooks between the two of them. "You don't need to be worried."

"Who said anything about being worried? Or replaced? I sure didn't use those words." Sunset flipped to another page.

Twilight bit her lip. "Look, I'm sorry for bringing her up; I know you don't like talking about her. But I promise, there's enough room in my heart for the both of you, and you don't have anything to be jealous about."

"Also not a word I used," said Sunset sharply.

"You don't need to say it; it's plain as day how you feel. And you don't need to feel that way! Starlight and I came into each other's lives at a very unique time, when she needed guidance that only I could give her. I mean, she was evil, tried to brainwash people, then repented of her evil ways and needed guidance to—"

"Oh yes. Such unique circumstances."

Twilight tossed her hands up with a groan. "You two are nothing alike, okay? Your situations are completely different. Just because I redeemed her with friendship after she tried to perform acts of unspeakable villainy, that doesn't make her..."

Sunset glared at Twilight.

"I mean, she, um..." Twilight coughed. "Sh-She's wracked with inner guilt and turmoil over her past actions. She... uh..."

Sunset raised an eyebrow.

"She has trouble... making new friends... and, uh, she..." It came to her in a flash of inspiration, and Twilight grinned triumphantly, clapping her fists together, and pointing her knuckles at Sunset. "She's purple!"

Sunset's eyelid twitched. She slammed her book shut, took a breath, and opened her mouth to speak.

The classroom door opened, silencing her preemptively.

"Sorry I'm late," said Twilight Sparkle's glasses-wearing, hair-in-a-bun-having, parallel reality counterpart. "I wanted to check up on a few things before I headed over here. Any new developments I should know about?"

Sunset sucked her teeth and looked away from the Twilight sitting next to her. "Nothing that springs to mind."

"Phew. I'd really hate to have spent so much time crunching those numbers only for something new to come along and throw all my data completely out of whack. Not that I don't enjoy crunching numbers, but I understand that you're kinda looking for expediency here."

She stepped into the room, shut the door, and glanced at Twilight, looking her from head to toe quickly with a faint blush.

"H-Hi, Princess Me."

"Hey, Other Me." Twilight waggled her fingers by way of a greeting. "You're looking awfully bespectacled today."

"Right back at ya! Except, uh, without the, um... because obviously, you don't wear glasses, and I just, I mean, uh..." Bespectacled Twilight coughed to clear her throat and shuffled into the classroom. "Anyway."

Sunset shut the book and slid off the table, dusting off her bottom and sticking her hands in her back pockets. "What've you got for me?"

"A theory. Not a whole lot more than that." She glanced at Twilight again, flicked her gaze over her counterpart's bare legs, blushed brighter, and stepped up to the classroom's whiteboard.

"This actually dovetails nicely with a project I've been working on since the Friendship Games – a working theory of interdimensional dynamics. In a nutshell, I posit that different realities float around together in a void analogous to outer space – farther-out-there space, if you will. Some of them are in closer proximity to each other than others. Our two realities are one such example."

Bespectacled Twilight picked up a marker and drew an irregularly shaped blob on the whiteboard.

"This is us, right? This is our reality. And this one... this one here is Equestria."

She drew another blob beside the first, their edges pressing together.

"Now, based on what little concrete info I've been able to gather on the subject, our dimensions don't just float close to each other. They lean against one another, their borders touching together. Along that point of contact, you can find the occasional spot where the border's a little weaker, places that make interdimensional travel possible. The portal in the statue, that's one spot, and an anomalous one at that, being a relatively stable means of travel between Ponyland and Humanland."

Sunset nodded her comprehension. "But how does that relate to the situation at hand?"

Bespectacled Twilight shuffled her feet and looked down. "Well, uh, recall if you will that a certain... someone... sorta opened a bunch of additional portals into Equestria and almost destroyed the fabric of reality."

She coughed again.

"If I'm right, then not all those portals opened into Equestria. A few popped up along an edge of our reality that didn't lean against another."

"So what did they open into?" asked Twilight. "Where'd Sunset's new roomie come from?"

Bespectacled Twilight drew a wide, asymmetrical oval around the two blobs.

"According to my figures, the only dimension leaning against ours is Equestria. We're surrounded, on all other sides, by literal nothing – the negative space between realities, in which all our universes float, the same way stellar bodies float around in space within a universe. Who's to say our friend didn't come from there?"

Sunset titled her head with a quizzical expression. "So you're saying, what, it came from outer space?"

"Farther-out-there space. But yes, that's my working hypothesis. As for why it's only manifesting now, after so much time has passed since the Friendship Games, I could not begin to speculate. If we could communicate with it, it'd make matters a lot easier, but for all we know, we're as incomprehensible to it as it is to us."

Bespectacled Twilight capped her marker and leaned against the whiteboard, partially erasing her drawing by mistake. She noticed, and scrambled away, smoothing out her skirt.

Sunset cupped her chin in her palms. "How do we make it go away?"

"That's another question that I don't actually have an answer for at the moment." Bespectacled Twilight's spectacles slid down her nose, and she pushed them back up with a fingertip. "B-But I'm sure that, between me and, uh, Princess Me, we can work out a solution."

"I concur," said Twilight with a nod. "I'll need access to your notes and research materials, though. And a place to stay, too. Do you think Pinkie Pie would mind another slumber party?"

"Uh... that's probably not an avenue we should pursue." Bespectacled Twilight chuckled sheepishly. "Pinkie's parents kindasorta think that you and I are the same person."

Twilight and Sunset stared quizzically at her.

Bespectacled Twilight flung her hands in the air. "I met them once and they thought I was you and they asked me stuff and I – I panicked, okay? Sue me!"

"So we say that you're twin sisters," Sunset suggested. "Easy peasy. Or, hell, just crash with me if you don't wanna go through the hassle."

"No offense, but I'm not sure I'm comfortable sharing a roof with your, um... houseguest." Twilight smiled apologetically. "I'll swing by Pinkie's and see if we can arrange—"

"Or you could stay at my house!" Bespectacled Twilight interjected. A grin bubbled on her face. "I-I mean, if you want to, anyway. It'd be convenient, since, you know, you need access to my research stuff. And my parents are gonna be out of town for a few days, too, so there's no risk of anyone asking questions they're not prepared to have answered. Plus, having the place to ourselves means there's no chance of anyone walking in on the two of us sleeping together!"

Twilight's face flushed beet-red to compliment her nonplussed expression. Her counterpart's face was a perfect, albeit bespectacled, mirror for her own. She turned around and planted her forehead against the whiteboard, quietly cursing her stupidity.

Sunset's and Twilight's eyes met.

"She's..." Twilight tapped her knuckles together. "She's not wrong, come to think of it. If we're gonna collaborate on this, then it's probably best that we spend as much time together as possible. Staying with her would make a lot of things easier."

"Yeah, yeah, I get it." Sunset blew a lock of hair out of her face and turned away. "She's another member of the Purple Pony Girl club."

"Sunset, that isn't what I—"

"So what about me?" said Sunset, her volume making Twilight recoil. "What am I gonna do 'til we get this sorted out? I mean, I'm the one who has to share an apartment with a thingy from outer space, if you'll recall."

"Father-out-there space," Bespectacled Twilight corrected, turning back around. "I don't know that there's any need to do anything, per se. The Eyeball hasn't done anything bad, right? Besides that thing with Flash Sentry."

A snorty giggle escaped her.

"Goodness, he's never going to be able to look at you as a sexual being again, is he?"

Twilight and Sunset shared a look of irritation that lasted until Bespectacled Twilight finished laughing.

"Anyway. If it's not acting maliciously, or giving any indication that it wants to hurt you, or even has the ability to hurt you, then why rush to judgment? Heck, maybe you could try communicating with it – if you can form some sort of rapport with it, learn something valuable, then it might help matters along a lot."

Sunset pointed at Bespectacled Twilight, frowned, and dropped her arm back to her side. "I can't actually find any fault in your logic. Much as it annoys me to admit it. Befriend a giant eyeball in my kitchen... not the weirdest thing I've done since coming here, I'm sure, but still. Pretty damn weird."

"Well, if you're uncomfortable with it, then you can always..." Bespectacled Twilight cupped her hands behind her back and looked at the ground. "Come and stay at my place? With Princess Me and I?"

Twilight looked at Sunset and gave her a frantic, anxious nod of encouragement. Chaperone, she mouthed.

Sunset glanced between the two Twilights. A smirk crossed her face for an instant. "Nah. I think I'm good. Let it never be said that a floaty Eyeball chased Sunset Shimmer out of her own apartment. And, wow, that sure was a sentence, wasn't it?"

"Off topic," said Bespectacled Twilight, looking up at the Princess. "But, uh, I have an experiment or two I'd like to run with you, as long as the two of us are together. Just, you know, stuff like, uh..."

She looked away, mumbling.

"Alleles, and measurements, and... whether or not the two of us look identical naked..."

Twilight slumped and groaned.

The original Writeoff version of this story was about 8k words in length. In revising and rewriting it, I accidentally tripled its size. Oops!

So I'll be posting the rest of the story in increments to make up for that.