Celestia wouldn’t talk to her about what she’d seen in the mirror.
What she was seeing.
A copy of herself, looking back at her, but with wings fluttering at her sides and a crown resting lightly on her head. It was was she wanted and deserved.
Sunset Shimmer sat in front of the mirror, staring at her own reflection. She’d been doing this almost every night despite Celestia’s direct orders against it. The room was sealed, with guards at the door and teleport wards keeping anypony out.
Or at least that was the theory - it had taken Sunset less than a day of study to decide that the castle's wards were the weakest link, and another week to crack them without setting off any alarms, something assassins and spies had been trying to do for decades. If money had mattered to her, she could have sold the secrets for enough to make her a very wealthy mare.
That had been months ago, and she hadn’t gotten anywhere since that. Years of work, and right at the end she was being held back by the pony who should have been helping her get through the last barrier.
“Then again, she has Cadance for that now. She doesn’t even need me.” Sunset grumbled, seething as she pictured the pink princess. Everything was going wrong. She stood up to pace. “If she hadn’t come along, I’d probably be a princess already!”
She turned to look at herself in the mirror. It didn't share her frustration. It sat serene and placid, watching her with an unreadable, detached expression. The same expression Celestia always had, that mask that said she was hiding some amusing secret that she wasn’t going to tell anypony. She picked up one of the books she’d brought and just barely stopped herself from throwing it at the mirror. Her reflection looked disappointed at her temper tantrum.
“No… too much noise and they’ll hear me,” she muttered. The doors weren’t entirely soundproofed, and if she caused a commotion she’d have to deal with explaining herself to a few stallions that already didn’t like her.
Sunset had a better plan today. She put the book back down, a spellbook she’d managed to sneak out of the restricted section of the library. Nothing had quite pointed to what she wanted, but this was at least a lead.
“Hopefully this time Star Swirl actually got something right that didn’t involve ceramics or facial hair,” she said to herself, going through the pages. They were written in backwards Horse Latin, which would be easy to translate if his hoofwriting didn’t look like he’d copied the spell’s instructions down while blindfolded, upside-down, with his head in a bucket of water.
Still, it was definitely something related to the enchantments on the mirror, and she’d translated enough to make an attempt at casting it.
“If I use this on the mirror, I should at least get some kind of a clue.” She braced herself, and cast the spell, forming the runes in her mind and closing her eyes to help her focus.
Vice-Principal Luna paced in front of the school statue, her mood souring. She wasn't sure what she liked less - it was a real toss-up between being forced to babysit when she had actual work to do, and the fact that her sister thought that looking after a child was an appropriate use of her time at all.
She should have been working on moving funding back to the after-school programs that her sister had been neglecting, but no, making sure a toddler was kept busy was obviously as much as she could handle.
"I'm not a toddler," the girl said, quietly. Luna looked down at her. The young girl flinched under the attention, bumping her head on the base of the marble horse. "I-I'm six. That's outside of the standard use-"
"It's impolite to correct your elders," Luna snapped, annoyed, partly at the child and partly at her own bad habit of talking to herself.
"Sorry. You were talking and I thought you were talking to me and..." she shrank down. "Sorry."
Luna took a deep breath. She was a little too good at her job of keeping the unruly students of Canterlot High in line, sometimes. Being the disciplinarian her sister failed to be meant that she sometimes wasn't aware of how intimidating she was.
"It's fine," Luna said. "Hopefully this won't be for nothing. Spending hours to try and convince a single student to attend the school is foolish."
"I liked Crystal Prep better," The girl said. She winced at Luna's expression. "I-I mean, I was doing research since I'll have to decide someday and they have all the awards and-"
Luna snorted and waved a hand. "All because my sister can't be bothered to follow their example and start winning. Instead she'd rather hand out participation awards and pat people on the back for trying their best."
The girl watched as the vice-principal paced.
"Can I assume you are able to amuse yourself for a few minutes?" Luna asked. Maybe she could at least get a few emails done while her sister played at being a salesman.
"That's why I brought my books," the girl said, holding the one she was reading up so Luna could see the title. "I'm almost done with Daring Do and the Secret Reptoid Masters! Mom said if I'm good, we'll go to the bookstore later and I can get the next book in the series."
"Fine," Luna said. "I'll be back in a few minutes. Don't go anywhere, don't talk to strangers. Just... stay right there."
Luna stalked off to her office, assuming there was no way the girl could manage to get into trouble in just a few minutes. One would think that having been a teacher in a high school she'd be aware that children could get into near-infinite trouble in mere moments.
The girl settled into reading her book, leaning back on the cool stone. For a few minutes, everything was fine, but just as she was really getting into the story, reading about Daring Do revealing shapeshifting reptilians on live television, she felt the marble behind her suddenly vanish, and she was falling backwards.
The world dissolved into a chaotic mess of lights and sounds. There was a sense of straining, like even her small body was too big to fit in the universe. Cracks spread through space. A sound like breaking glass and tearing metal echoed across the cosmos.
There was a sensation like a round peg being forced through a square hole, but the holes were in extra dimensions and the parts being sheared off included something very important that she was already starting to forget, like the fading details of a dream.
“Something’s happening!” Sunset leaned closer to the mirror. This was it! This was going to show her the secret to reach the next level! Her reflection had disappeared, and the surface of the mirror had started to ripple like a stone dropped into water.
There was a shape forming in the distorted reflection. Sunset narrowed her eyes, trying to make it out. It looked small, it seemed to be moving, and it was-
“Purple?” Sunset asked, just before something smacked into her head hard enough to send her to the floor in a heap, stars dancing as her vision faded to black.
Something prodded Sunset’s chest. Her head was pounding, and she could feel a bruise forming already.
“Please wake up…” The voice sounded terrified, not just at the edge of tears but beyond it and crying openly.
“Mmmrphm.” Sunset said. It made more sense in her mind, before the concussion and semi-consciousness reduced it to a noise instead of a word. She opened her eyes, blinking slowly to try and clear her vision. Everything was sort of wobbly and detached. Probably because of the massive, pounding headache.
“What’s going on?” Asked a tiny, terrified voice. Sunset looked at the source of the noise. A filly. Couldn’t have been more than six or so. Very purple. Just like the thing she’d seen in-
“The mirror!” Sunset gasped, stumbling to her feet to look. What she saw made her eyes go wide. The glass had gone cloudy, and a crack had formed across it. She could still dimly feel the enchantment there, but it was very badly damaged.
“It’s not my fault!” The filly said, cowering.
“No, this is- I must have messed up the spell.” Sunset slumped, sitting down in defeat. “It’s not like a filly like you could damage an artifact even if you tried.”
“A filly? I’m not a filly.” The filly looked up, frowning.
“You’re not a colt, and you’re a little young to be a mare,” Sunset snorted. “How did you even get here?”
“I don’t remember,” The filly whispered. “I was falling, and then… and then I woke up here, a-and I can’t remember anything before it. I-I don’t know what to do!” She started crying. Loudly. Sunset heard the doors start to open.
“Horseapples... “ Sunset whispered, looking back at the door.
“What’s going on in-” the first guard stopped speaking when he saw Sunset. “You’re not supposed to be in here! How did you get in?”
“She’s got a filly!” The second yelled.
“Sunset Shimmer, you’re under arrest for foalnapping!”
“I didn’t foalnap her!” Sunset yelled. “She just appeared!”
“That’s Shining Armor’s sister!”
“She foalnapped Shining Armor’s sister!”
Sunset looked at the filly. “Okay, great, now we know where you came from.” She picked her up with her magic. Tried to pick her up with her magic. Instead there was a sharp, stabbing pain in her sinuses and a shower of sparks as the spell failed. “...Crapbaskets.”
“Get her!” The guards yelled, piling into the room.
“Help!” The filly yelled, grabbing Sunset’s leg and tripping her, dashing any hope of escape.
“This is just not my day.” Sunset groaned, before the butt of a spear sent her sprawling to the ground.