Sitting on her haunches on the eastern balcony of the Crystal Spire, Princess Celestia had just finished raising the sun when she heard the distinctive buzz of changeling wings approaching. She turned around to see Twilight and five of Cadista's drones landing behind her, in the room just beyond the balcony door.
"Princess Celestia," Twilight exclaimed hastily, "a unicorn just entered the castle and stole the element of magic. Then she left through the magical mirror on the eleventh floor."
Taking only a moment to note that despite having practiced to just call her 'Celestia' outside of formal situations, Twilight still relapsed to calling her 'Princess' when she got panicked, Celestia was quick to put two and two together. "Can you describe this unicorn?"
"Yes. Yellow coat, wavy red and yellow mane and a cutie mark with a red and yellow sun of sorts. Why? Do you know her?" Twilight quickly answered, lighting her horn to project an illusory image of the unicorn in question in the space between her and Celestia.
Celestia took one look at the image, barely listening to the description, and sighed quietly. "I'm afraid yes, I'll explain in a bit. Inform Queen Cadista of what happened, then go wake Spike and your friends. I'll fetch Luna, Cadance and your brother. Meet us in the throne room." With that she turned back around and took off to fly around the spire to the opposite balcony, where she knew Luna would still be sitting after raising the moon. Twilight silently dismissed the drones to return to their posts, leaving only Gilded Shield at her side as guarding her was the post she had been assigned, before pinging Cadista to inform her of the situation whilst taking off towards the hallway that led to the chambers her friends and Spike were likely still sleeping in.
Gilded took only a split second to marvel at the multitasking ability the young queen displayed before taking off to follow her.
15 minutes later, everyone was gathered in the throne room. Both Cadence and Rarity could only be brought to leave their rooms after their manes had been tamed with a generous helping of magic form Celestia and Twilight respectively. Both silently envied Applejack and Fluttershy whose manes were miraculously behaving after just one shake of their respective heads. Only Rainbow sported a sizeable bedhead that Rarity's magic was idly fiddling with. The pegasus had given up telling her to stop five minutes ago.
"The unicorn you encountered, Twilight," Celestia spoke up, "is Sunset Shimmer." Cadance's eyes widened slightly at the name, but nopony else showed any sign of recognition.
"She was my personal student and protégé before you and left only a few months before your entrance exam. She was a lot like you once: curious, talented, eager to learn and, after some training, a very skilled sorceress. But where you were isolated and sometimes picked on, she chose the opposite path, she became cold and controlling, and her heart turned dark. After she left, I could have sealed the mirror, but I chose to leave it open, hoping for her to see the light in the world beyond and one day return to seek forgiveness. It seems that now she has returned. But for a different reason."
At this point Celestia fell silent and Luna seamlessly took over. "You must retrieve your crown from this other world. Without it the other Elements are powerless and Equestria is vulnerable."
"Not to mention," Celestia took over once more, "the consequences of taking such a powerful magical artifact into another world. We know little of this other world but we can assume that introducing the element there, perhaps even without using it as Sunset Shimmer undoubtedly plans to do, would have equally dire consequences as removing it here."
The group of ponies and the one dragon riding atop one changeling had slowly been walking through the spire and were now coming to a stop in the mirror room.
"I must warn you, Twilight Sparkle," Luna spoke up while rolling her eyes as she magically removed Pinkie's forehoof from the mirror's surface, "this mirror only opens for three days once every 30 moons. As it opened tonight that means you only have until midnight two days from now before it closes again."
"Well? What are we waiting for? Let's go!" Rainbow spoke up
Pinkie bounced gleefully "Ohh this is gonna be great, a whole other world to explore."
"I'm afraid not" Celestia interrupted, casually ignoring Pinkie stopping mid-bounce to hover in the air. "The Element's presence is disruptive enough, sending all of you could offset the balance further."
"Don't worry girls," Twilight addressed her friends, "I'll be back soon." With those words she took a deep breath, stood up straight, and stepped through the mirror. The last thing she heard were encouraging words from her friends followed by gasps and the clicking of tiny claws on the crystal floor.
When Twilight's head stopped spinning she opened her eyes and saw ...
Stone.
Once her sense of balance decided to respond again she realized that she was staring at the floor. Well, that would account for the pavement. So far so good.
"Twilight, are you okay?" The voice of Spike shook her from her contemplations. Looking up to where the voice had come from she saw a dog. A purple dog with green ears and a tuft of green fur on the top of it's head.
"Spike?"
"Yup."
"Are you a dog?"
"Seems so. I have no idea what you are, though."
"What do you mean?" Twilight lifted her forehooves to find, that she no longer had forehooves. Instead she found strange claw like appendages, but without talons. The shape seemed remotely familiar, but she couldn't place where she had seen it before. As she tried to move the strange appendages, only to find that she could, her mind started to lock up in panic.
As she was about to start screaming she felt her panic suddenly falling away, together with the gentle touch of Queen Cadista on her mind. <Calm, Twilight, I assume you're in a complicated situation but panic won't get you anywhere.>
<Cadista?>
<Yes. It seems that the portal you used can serve as a conduit for the hive mind, we're still connected.>
<Well that's at least something>
<Indeed. Now if you want to find your crown you will need to fit in wherever you have ended up. Look around, what do you see?>
Looking around Twilight saw a large building of red brick forming what seemed to be a U-shape with large doors right in the center and a dome above them. Approaching the doors from all directions and entering the building were many tall, slender creatures that, to her surprise, seemed to be walking on two legs. Looking closer, she noticed that they had the same appendages that had replaced her forehooves.
"Okay so I have these forehoof thingies that they have" she muttered to herself "Spike, does the rest of me also look like one of those?" she asked, pointing at a few of the strange creatures ahead.
"Looks like it. Now that I think about it, they remind me of these 'Human' creatures Lyra keeps going on about."
"Right, Lyra. That's why these things seem so familiar." she motioned to her altered forehooves, "These are hands, she showed me a drawing of them once. Well if I want to fit in, I suppose I should try figuring out how to walk on two legs." Slowly standing up, she wobbled for a moment before stabilizing on her unfamiliarly long legs. So far, so good. Turning around, she saw a tall statue on a tall pedestal with pillars framing polished stone. The surface she was facing had a sheen of magic to it and when she tried touching it she felt her new hands submerge into it like water.
"Well, this looks to be the way back to Equestria. Now to find the crown."
Still slightly unstable, she approached the large brick building. By now the humans from earlier seemed to be inside with only a few still coming in here and there. She walked up to the doors instinctively trying to have them swing open with her magic only to feel nothing. She might have been able to stop in time were it not for her unfamiliarity with her new legs. As such, she crashed into the glass of the doors, feeling a jolt of pain from her strangely shortened muzzle.
"Uhh Twilight I don't think you can use magic here. You don't exactly have your horn."
"Wait, what?" She tried to look up but couldn't see any trace of a horn. Then an idea struck her. If I'm still connected to the hive mind that must mean that my psychic powers are intact and I don't focus those through my horn. "Hold on, I'm going to try something." She focused her mind on the door tried to use her psychic powers to replicate the effects of her telekinesis. After a short moment of trying different ways to focus, the air around the doors seemed to warp slightly and the doors swung open.
"Whoa, how'd you do that?" Spike asked, staring from the door to Twilight and back.
"Psychic power," Twilight explained with a smirk. "as Yumia put it: 'It's good to be the Queen.',"
"So that's something changeling queens can do?"
"Yes, although simply using magic for something like this is usually easier." Now that she had cleared her mind she realized that she was starting to pick up emotions around her. Mainly there was a background aura of mostly boredom with a bit of frustration which, Twilight had found - to her great surprise - seemed to be commonly found in and around schools, but there was also something else coming from her left. Two sources, one giving off anger, the other giving off fear. "Come Spike, I think something is happening."
As they approached a corner, they slowed down, stopping next to the edge. Peeking around the corner Twilight saw two girls, both with yellow skin. The closer one had her back turned towards her. Despite that, her golden yellow skin and wavy red and yellow hair were easily visible, Twilight found her to be the source of the anger. The source of fear seemed to be another girl with pale yellow skin and equally pale pink hair. Despite facing towards the corner she was watching from Twilight couldn't see her facial features as they were largely hidden behind her long hair.
As she watched, the second girl spoke up in a quiet voice that Twilight found to be eerily familiar, "Oh, I'm really sorry. I-I just found it, and-and I thought I should give it to her. I didn't know you had dropped it. "
"Well, I did!" The first girl closer girl answered in a voice Twilight was certain she had never heard before. "And I was about to get it before you swooped in and ruined everything! You shouldn't pick up things that don't belong to you."
"It ... doesn't really belong to you, either." The quiet girl answered in an even lower voice than before but Twilight could feel a trace of determination mixing into her fear.
"Excuse me?!" The other interrupted incredulously, her anger now tinged with surprise.
"N-n-nothing..."
"That's what I thought. It's as good as mine, and you know it. You really are pathetic. It's no wonder your best friends are all stray animals." Twilight had heard enough. She leaned back before stepping around the corner and raising her voice.
"How dare you speak to her that way!"
"What did you say?" This time there was a clear note of surprise. Twilight felt the bully's anger shift towards her but her determination was stronger.
"I said, 'How dare you speak to her that way?'!"
"You must be new here. I can speak to anyone any way I want." Throwing closed the locker Twilight only now noticed they had been standing before, the hot headed girl strutted off towards a staircase at the other end of the corridor.
Twilight sensed the quiet girl's fear giving way to relief, confusion and a touch of admiration. "I can't believe you did that!"
"I couldn't just stand there."
"Well, it's just that nobody ever stands up to Sunset Shimmer." Her admiration only seemed to grow at Twilight's apparent lack of fear towards Sunset.
"Sunset Shimmer!?" So that's how she looks here. Of course, the hair, coat - no wait, not coat, skin - I should have guessed.
"You've heard of her?"
You can say that again, she's the reason I'm here. "Sort of..."
"I don't think I've seen you around before. Did you just transfer to Canterlot High from another school?"
So it is a school! "... yes! Another... heh, school! My name's Twilight." The other girl gave a quiet sound that Twilight could guess were words but couldn't hear well enough to understand. "Sorry, what was that?" After an even quieter repetition Twilight was getting a sense of deja-vu, "It sounds like you're saying Fluttershy, but how can that...?" In that moment Spike followed Twilight around the corner from where he had still been watching.
"Oh, my goodness! Who's this sweet little guy?" The girl exclaimed, her shyness suddenly gone, a wave of joy almost knocking Twilight off balance.
"That's Spike! My, uh ... dog!" Twilight explained, still unused to Spike's new species. Fluttershy, meanwhile, picked up Spike in one arm while reaching for her bag with the other grabbing some dog treats from a side pocket.
"Oh, he's so cute! Go on, eat up, little pup!" Spike was still confused by the whole situation but wouldn't deny getting free food. "Oh, wouldn't you just give anything to know what they're really thinking?"
"He usually just tells me." Twilight replied, confused.
"Oh, w-what do you mean?" Fluttershy's confused reaction and a bark from Spike reminded Twilight that dogs couldn't usually talk.
"Oh, uh, nothing! Never mind. Sunset Shimmer said you picked something up. Something that belonged to her. It wasn't a crown, was it?"
"How did you know?"
"Uh, lucky guess? Do you still have it?" Fluttershy shook her head "But you know what happened to it." A nod.
"I didn't want anything to happen to it, so I gave it to Principal Celestia"
"Principal Celestia? She's the ruler here?"
"You could say that. Technically, I guess she and Vice Principal Luna do make the rules."
"Where is she now?"
"Probably in her office. Third door on your left." Fluttershy pointed out an unassuming door a few meters down the hallway.
"Thank you!" Twilight turned towards the door, while Fluttershy's gaze followed her for a short moment before settling on Spike.
"Oh, wait! You're not really supposed to have pets on school grounds." Twilight turned around, confused. "Might wanna tuck him into your backpack. That's what I do." As Fluttershy's backpack opened a snow-white cat, a small red bird and a very familiar looking white rabbit hopped out. "They just get so lonely when I'm in school all day." As Twilight took in the scene, there was one thought on her mind.
Same old Fluttershy. Even if she's from another world.
Twilight gave the shy girl a genuine smile, the task of not scaring her made much easier by the fact that she didn't currently possess fangs. "Oh, okay! Thank you!" As she got to the significant task of practicing to control her new hands to take off the backpack that had appeared along with the clothing she now wore, the loud ringing of a bell filled the hall for a short moment.
"Oh, no! I'm late for class!" Fluttershy gave a worried frown before swinging her backpack low to the floor, scooping up her animals in it and placing it on her back. As she ran off towards the end of the hallway Twilight could make out two white paws pulling the backpack closed.