An irate unicorn filly stormed through Canterlot Castle, her vibrant red and yellow mane framing puffy teal eyes. The yellow fur coating her cheeks was matted and wet, and the trembling of those eyes betrayed the presence of more tears waiting to come forth.
As she entered the castle’s library, she only cast a brief glance around to check that there was nopony present before she couldn’t hold her frustration in any longer.
“It’s not fair!” Sunset Shimmer shrieked at the top of her little lungs, slamming the door behind her with a burst of magic to punctuate the last word. She sniffed once, making one last-ditch effort to hold her composure, but her legs were already trembling as the adrenaline faded. She swayed in place then flopped unceremoniously into a heap in the middle of the room.
Fortunately for her already frayed ego, nopony had been around to witness the spectacle she'd made of herself. In fact, while marching through the barren halls, her inner drama queen had latched onto the idea that the castle staff and guards were going out of their way to give her space. True or not, the filly had been spared from further embarrassment.
“A new student. Why does Celestia need a new student?” She sneered, her tone shifting to a cruelly mocking one. “Was I not good enough, not smart enough for the princess’ liking? Weren’t my studies progressing well? Wasn’t Celestia always praising me for how quickly I learned new lessons? So why on Equis does she need another personal student?!”
Her eyes focused on the shelves, her nose taking in the familiar, stale scent of dust and paper. Some ponies might argue that paper doesn’t have its own scent, but she had spent more than enough hours within these walls to know it distinctly. “All these books… I’ve read almost everything in this library, now.”
Her frown deepened, eyebrows furrowing as another suppressed thought bubbled to the surface. “Princess Celestia knows that… She should know I’m more than ready for something new. I’m ready to learn advanced magic!”
Sunset snorted, lowering her muzzle to her hooves. “What, did she think I wouldn’t notice that we’ve been circling around the fundamentals over and over lately? If I learn so quickly, then why is she holding back?” She closed her eyes, trying to understand what her mentor could be thinking, but could only bring herself to one conclusion.
“I’m being replaced…” Sunset choked out a sob, burying her face in her hooves. Every hopeful image that came to mind was immediately and thoroughly squashed by nightmares of Celestia throwing her out in favor of somepony smarter and better than her. A small part of her knew it couldn’t possibly be the truth, that she had to be overreacting, but that thought was being thoroughly suppressed by the rest of her emotional filly mind dedicating itself to being utterly miserable.
She sniffled and looked around once more. Nopony was there aside from herself. Nopony to see her get up on unsteady hooves and wander to the back of the castle archive. Rather than head for the door to her bedroom, which lay at the back of the library, she took a twisting path through the shelves and corners that filled her home away from home. Eventually, she reached a dusty part of the room that nopony but her ever visited. She pressed on, occasionally stopping to wipe away a tear. Her mind was resolved, and she was running out of tears to shed anyways.
Sunset reached out to press an otherwise unobtrusive stone into the wall, at which point a shelf slid away to reveal a staircase leading downwards. She lit her horn and descended, following one of the castle’s innumerable secret passages down to a place which had held her interest almost exclusively for the past few months.
She knew exactly what awaited her at the bottom of the spiralling stairs: an ancient laboratory which contained an equally ancient mirror. The mirror was actually a portal—a gateway to another world.
She had stumbled upon it about a year ago by accident, having bumped into the switch while searching for new study material in the library above. It appeared to have lain dormant and untouched for countless decades, maybe even centuries, and from that moment on, she’d been determined to study it in secret. Oh, she knew she should bring it to Princess Celestia’s attention eventually, but she wanted to do so with a full and complete research report detailing everything there was to know about it. Imagining how proud her teacher would be of her when she did so was something she looked forward to like nothing else.
‘I guess that won’t be happening now…’ Sunset thought bitterly, continuing her descent.
An ancient stone archway awaited her at the bottom, the old wooden door having long since fallen off its hinges and rotted away. In stepping through the empty arch, she entered what could only be described as an underground laboratory, at the center of which stood a grand and beautiful mirror, seemingly untouched by the ravages of time.
“O-okay,” she said to herself, pausing to sniffle and wipe her nose, “I know when I’m not w-wanted. Maybe I’ll just stay here with my r-research…” Sunset sighed, taking a deep breath to steady her voice. It only served to drive home the ache in her chest. “Maybe… or maybe I should just leave…”
A strange sense of deja-vu washed over Sunset Shimmer, more powerful than any fleeting sense of it she’d ever experienced. It was as though, suddenly, she knew she’d seen that moment play out once before, exactly as it had up until then. She glanced around the room, hoping to find its source, but nothing in sight seemed to have triggered it.
The strangest part was the feeling hadn’t passed, and it showed no signs of doing so soon.
She tried to shake it off while she slowly walked up to the mirror, noticing that the normally dormant gems on the frame of the mirror were lit. A test prod with her hoof showed a ring of light surround her foreleg as it dipped below the metal surface with nary a ripple.
“Active, just like all my research said it would be,” she muttered while closing her eyes. It was late, she realized. Fairly close to midnight, in fact, and it was the last day the portal would be open for another thirty moons. Once the clock struck midnight, it would close once again.
In the past, every test object she had levitated through it had come back perfectly intact—at least, as far as she could tell. However, despite how impatient or impulsive she could be known to be, she had yet to set foot through the portal herself. She had no idea what sort of world waited on the other side.
“All it would take is a few steps, and Sunset Shimmer, child prodigy and former personal student to Princess Celestia, would be gone. Maybe in this other world, they’ll appreciate me…”
Using her magic, Sunset lifted her quill, ink and a piece of parchment from her makeshift work desk. She began to write, leaving her final message for the princess. With nopony to close the secret passage behind her once she was gone, it wouldn’t take long for it to be found.
Dear Princess Celestia,
I’m leaving. It seems to be what you want. I didn’t understand why you won’t advance my studies, but now I think I know. I didn’t need you holding me back, anyways.
Your former student,
She sighed as she looked down at what she’d written, then put it on her desk with the rest of her tools. It was terse, crude and barely said anything, but she didn’t care anymore. She no longer wanted to think about it.
Sunset started to step into the portal, but she hesitated. ’I need to think this through, though… I’ll be going to an unknown world with no idea whether I can secure food or shelter. I’ll be there for thirty nights, at minimum, with no way to come back for supplies or a bed to sleep in.’
The deja-vu was growing stronger as she got closer to it, like a cold ache within her chest. She looked down at her hoof in front of the mirror with the sensation that she was seeing it twice, then imagined herself stepping through. In her mind’s eye, she saw the empty room as the portal faded. Briefly, she wondered whether it was a vision or her own imagination and then tried to concentrate on that feeling to see if she could see further.
What she found herself seeing, instead, were memories of her time under Celestia’s tutelage. She remembered the joy she’d felt when she was chosen by the princess for private mentoring. Study sessions with the princess when she was just beginning to learn her gift, where she often fell asleep at the motherly alicorn’s side. The first time Celestia tried to teach her proper dining etiquette, and the clumsy filly accidentally flipped an empty teacup on top of her head, where it had landed like a hat. They had both broken into giggles at that one.
She bit her lip, backpedaling a few steps while her mind began to rationalize. ’Well… what if it’s not even inhabitable? I could be stuck on a moon or something, or land in the middle of a desert… I never tested for atmosphere or environment…’
She sighed and thought about her options. It had been hours since Princess Celestia left to meet her new student, and she was no doubt back by now, but Sunset had no intention of going to face them yet. When the princess surprised her with the news, Sunset just felt numb. She did her best to hide her feelings until Celestia left to pick up this ‘Twilight’ filly—then, she spent most of the day sulking in various parts of the castle, eventually working herself into the rage which had led her to the library.
And yet… something was telling her that it was all wrong. Maybe it was the strange deja-vu which continued to linger. The more she thought about it, the more she realized she hadn’t even given the situation, or the princess, much of a chance. Maybe it wasn’t as bad as she thought? Maybe she should at least go find out first. At worst, she’d just have to tough out whatever happened to her for another month, and then she could sneak back down there and leave if things didn’t work out.
She made her decision, and when she did, the sense of deja-vu vanished at last. Try as she might, Sunset still couldn't figure out what had caused it. With a shrug and a heavy sigh, she rubbed her eyes to remove any last traces of tears and turned towards the stairs. A last flick of her horn tossed the letter into an old empty fireplace, where she incinerated it. “Besides,” she murmured to herself, not noticing the mirror going dormant behind her, “I forgot to bring Smarty Pants. I’d never forgive myself if I left without her.”
After a night of fitful sleep, the morning brought with it a sense of calm and acceptance. Sunset blearily rolled out of bed, yawning as the rays of sunlight streamed through the window. She made her way to the door, scooping up her doll and placing it on her back before she left for breakfast.
She heard both a familiar and an unfamiliar voice as she approached the royal breakfast nook, causing her to take a breath to steel herself before she entered. The first one she saw was the princess herself, laying serenely upon a pile of pillows in the center of the room while sipping her morning tea. Next to her sat her would-be successor: a tiny unicorn filly, barely out of foalhood, topped with a purple mane which had a thin stripe each of violet and magenta. Her coat was a lighter purple, closer to lavender, and Sunset felt her eyes drawn to the filly’s flank—a cutie mark depicting a six pointed starburst was already present, even at her age. The filly was busy doodling in a notebook with a red crayon, oblivious to Sunset’s entrance.
Celestia’s soothing voice carried over to the doorway, snapping Sunset from her reverie. “Good morning, my faithful student.” She smiled warmly, beckoning her in with a soft, downy wing. The filly looked up at this and shot Sunset a nervous smile, but inched back underneath Celestia’s other wing.
“Don’t be shy, Twilight,” said Celestia, gently nudging her forward again with her wing. The filly peeked back out again, the princess’ white feathers all but covering her eyes, and she stared at Sunset for a moment before looking back up to the princess again.
Princess Celestia smiled warmly down to Twilight, which seemed enough reassurance for her to come out of hiding and take a few steps forward. Sunset finally snapped out of her trance and walked into the room, letting the door close behind her.
“Twilight Sparkle, this is Sunset Shimmer, my senior student. She’s actually just a few years older than yourself.” Celestia smiled, nodding to Sunset. “Sunset, this is Twilight Sparkle. She caused quite a commotion at her entrance exam the other day.”
Sunset looked from Twilight to Celestia, then back a few times, trying to decide what to do. After a minute of doing so, the princess started to look a bit concerned, causing her to finally screw her courage to the sticking place and put voice to her worries. “Princess? Is she… Are… Are you replacing me?” she croaked out, trying not to let her eyes start watering again.
Princess Celestia blinked a few times in shock at the question. She wasted no time in pulling Sunset in close and giving her a warm, gentle hug. “Sunset, what ever gave you that idea? Nopony could ever replace you,” she cooed. “You are an extraordinary young filly who I am proud to have as my student. That will never change. Twilight has proven herself to be extraordinary, as well.” She smiled, watching as Twilight emerged from her other wing to sit in front of and look up at the two of them. “I believe the two of you will accomplish great things together. It will be my honor to teach you both.”
Sunset hugged her mentor close, burying her face in her soft feathers and fur. All her fears were finally laid to rest, and all the stress and anger from the last few days finally left her. She might have stayed that way for the rest of the morning, but the smaller filly spoke up to get her attention.
“Miss Sunset?” asked Twilight, drawing her to look down as the lavender filly pulled her notebook and crayon up with her magic. “Before we go any further, could I get you to answer my questionnaire?” she asked in an adorable attempt to sound official.
Sunset couldn’t help but smile a little while she nodded. “Okay?”
Twilight smiled and adjusted an imaginary pair of glasses. “Vewy good. Do you like any of the following: Books?” Sunset nodded. “Hugs?” Another nod, with a hoof trying to hide her growing smile. “Cookies?” She nodded once more. “Baby Dwagons?”
Sunset tilted her head and raised a brow at the last one, but shrugged. “Sure, why not?”
Twilight nodded and scribbled away at her notebook, sticking her tongue out the corner of her mouth. When she finished, she turned it around to reveal a venn diagram showing two large circles—one marked ‘Twilite’ and one marked ‘Sunset’—with all the mentioned topics written in the intersecting portion in the middle. “Okay! According to my data, which I painstakingly gathered using only the suwest of scientific methods, I have determined that we are compatible.” The young filly nodded and smiled, satisfied with her results.
Princess Celestia gave a soft, tinkling giggle, and Sunset couldn’t help but smile widely at Twilight before walking out from under the princess’ wing, using her magic to float Smarty Pants over to the younger filly.
“You know what, kiddo? I think we might be, after all.”