"What a fascinating contraption," muttered Nightmare Moon, walking alongside the train. She reached out, tapping a piston with one hoof.
"You've never seen a train before?" asked Rainbow Dash, hovering just above the small unicorn Nightmare had disguised herself as.
"We did not have such things in my time," she replied, "and while Luna saw a few during the years I was imprisoned in her mind, she never concerned herself with them much. You say they are used to transport ponies and goods at high speeds?"
"That's right. Well, not as fast as me, but still fast."
"Hmph." Nightmare Moon let out a snort. "You're awfully proud of your supposed speed for a mere pegasus. I doubt you can even compare to an alicorn such as I."
"Wha-bu-pffpth!" Dash started sputtering so hard she almost fell out of the air. "If we had time, I'd take you on in a race right now! I'd enjoy wiping that smile off your face!"
"I'd enjoy searing the flesh from your bones."
"W-what was that?"
"I said, I'd be glad to accept your challenge of a race."
"Oh." Dash looked confused for a moment, but shrugged it off. "Any time you want then, babe. I'll show you how fast a 'mere pegasus' can be!"
"Let's see how fast you are without any flesh on your bones."
"What?"
"I look forward to the race."
"Hey!" Both ponies looked over to the other end of the platform, where Shining Armor was waving to them. "Looks like Celestia is coming. We'll be ready to go soon."
They walked over to join the other ponies, which included everyone but Celestia, Rarity and Applejack. Stopping next to Shining Armor, Nightmare Moon looked down the street and spotted the small group trotting to meet them.
Celestia—or 'Sunny Skies', as she called herself while in her pegasus disguise—saw Nightmare Moon at the same instant, and froze in place. After a moment she resumed walking, one eye twitching, the air around her shimmering slightly.
"It looks like she's calmed down a bit," noted Nightmare.
Shining Armor watched as a row of potted plants briefly ignited at Celestia's passage, and nodded.
"Yeah, she's doing a lot better."
"I don't see why I must go in disguise at all!" cried out Nightmare Moon, stomping around Twilight's library.
"Did you completely miss Celestia talking about the need to do this quietly?" asked Shining Armor. "I thought you were in the shadows, watching everything. We want to draw as little attention as possible to the fact that three of the Princesses are gone, and 'The Return of Nightmare Moon' kind of goes against that."
"Would that not make an excellent cover for why they've been turned to stone? It is one of the plans I'm considering. Was. Was one of the plans. Past tense."
"No, that would be a bad cover, because then all of the Royal Guard would be after you!" Shining Armor rubbed his temple with one hoof. "Look, is this about the armor? Are you scared that you won't be wearing it while disguised or something?"
"Scared?! You impudent little foal!" Nightmare Moon turned, rearing up as lighting crashed through the sky outside and thunder shook the castle. "I should flay you where you stand—I mean, no I am not scared. There is little I fear. Besides, the armor is… a part of me, in a way. Disguising myself will have no effect on it."
"'There is little you fear'?" Shining repeated, cocking his head to the side. "Does that mean there is something you're afraid of?"
"There is nothing aside from Luna's—there is nothing." Nightmare Moon turned away, shoulders tensed.
"Well, if you're afraid to talk about it…"
Shining Armor made the mistake of trying to deal with Nightmare as though she were his own little sister, and immediately regretted it. Nightmare Moon exploded into a black mist, swirling around him like a tornado, except it was a vortex of ice-cold air that raised a deep fear in him, a dark, primal fright greater than anything he'd ever experienced before. Finally, she reformed, towering over him.
"Fine, you wish to know what I fear? It is being returned to Luna's mind." She shoved a hoof into his chest, sneering down at him, sharp teeth exposed in a furious grimace as magic crackled around her horn. "Have you ever been locked in someone's mind? Able to see and hear everything but do nothing? Just sitting there, brooding, your failures rubbed into your face with every sunrise, with every smile from Celestia…
"And there were… worse things in there…" she trailed off.
"Okay, I'm… I'm sorry," said Shining Armor as she turned away again. "I shouldn't have asked."
"Hmph. This disguise idea should never have been brought up."
"Well, it was. The whole plan relies on us not drawing attention to ourselves, and we can't do that if everypony recognizes you and Celestia. I suppose you can stay behind, if not disguising yourself is so important. Though I'd expect you'd have to stay out of sight in that case."
"Stay behind…" Nightmare Moon frowned at a bookcase. "No, I can't do that. You might need me, yes? To… help."
"It would be a help, yes, even if I don't exactly trust you," said Shining Armor, nodding. "Celestia is confident that she could even do this alone, but I'm not. And we can't risk those four being trapped in stone forever."
"No, no… can't have that…" Nightmare Moon, still facing away, grinned. "Why, that would ruin … everything."
She strode out to the center of the library. "Very well! Prepare to witness my power, and the glory of my… ugh, normal pony form."
Magic glowed in her horn, bolts of power arcing out and growing to envelope her entire body. Her head tilted back as she was lifted off her hooves, and the light began to shift, shrinking down, her wings vanishing, until she disappeared completely in a cloud of black smoke.
"You know," coughed Shining Armor, waving a hoof in front of his face, "when the others do that, it's just a flash of light."
"That's because they don't understand what it means to wield true power," declared Nightmare Moon, emerging from the smoke. She sniffed, and angled her head to the side to peer down at him out of one eye. "Behold, and bask in my—"
She stopped, realizing she was staring at his hooves. Tilting her head back to look up at his face, she let out an indignant cry. "What mockery is this?!"
"Uh…" Shining Armor began to back away nervously from the small unicorn, who was barely half his size. "I think I see your point about this being a bad idea…"
"I can't believe this," griped Nightmare Moon, glaring down at her body. "I am the Queen of Nightmares! I should not have a form that looks fit for a filly, even as a disguise!"
Continuing to complain, she didn't see the library doors opening. Shining Armor noticed, and, seeing the worst thing that could possibly happen entering the room, quickly threw a shield around himself and Nightmare Moon. Instantly the unicorn went into a battle stance, igniting the magic in her horn.
"Hah! Now you show your true colors!" she cried triumphantly, not noticing as something thumped against the shield behind her. "You think to defeat me while I am small and weak? To trap me in your pathetic idea of a shield? I'll rip it, and you, to shreds!"
"I'm not attacking you," said Shining Armor, pointing with a hoof. "I was protecting you. From… that."
Nightmare Moon turned. Standing on her hind hooves, spread-eagled against the shield, was Celestia. Luckily she was in her Sunny Skies disguise, otherwise Shining Armor would have had no chance keep the shield up; he was straining as it was. Celestia's forelegs worked incessantly, pounding and clawing at the shield. Her face was hard to make out, due to the fact that her mouth was constantly opening and closing, but even Nightmare Moon at her worst had never looked more frightening.
"Oh." Nightmare tilted her head, watching Celestia's frantic efforts to get through the shield and, presumably, wrap her hooves and/or any other convenient nearby object around the small unicorn's throat. "What's that about?"
"Well, this, probably."
Shining Armor held up a mirror. Nightmare Moon took a look in it, froze solid for several seconds, then fell to the ground rolling in helpless laughter.
Her hair was a light, silvery blue, cropped close to her head, a few loose bangs falling down above her eyes. Her coat was a deeper blue, more violet, and her cutie mark was a moon on a black cloud. And, of course, she was small, significantly shorter than the average mare.
She looked for all the world like a young Luna.
"Oh, this is too good!" she howled, unable to stand, pounding the floor with her hooves. "It's so perfect! I couldn't have planned things better if I'd tried! I just… I just wish I could hear what she's saying right now."
"That is odd, there's no reason sound shouldn't be carrying through the barrier." Shining Armor frowned and peered closer at Celestia as her mouth moved. After a moment, he backed away from her as far as he could, bumping against the inside of the shield. "Is she… is she gnawing on the shield?"
That sobered Nightmare Moon up in a hurry, and she quickly joined Shining Armor on his side of the shield.
"Okay, I'm the Queen of Nightmares, and that's even freaking me out." She gave Shining Armor a grudgingly appreciative look. "Thanks for the shield, I guess. I'd rather not tangle with… whatever that is."
"Well, Celestia told me to guard you. That means stopping you from hurting anyone, and it means stopping you from getting hurt. It also means not letting the two of you get into an all-out brawl in the middle of Twilight's library."
They were silent for a moment as they scurried back to the center of the bubble and away from the snarling beast that was now stalking around the perimeter of the shield, foam dripping from its mouth.
"So, how long do you think it's going to take her to calm down?" asked Nightmare Moon.
"Big Sis!" cried Nightmare Moon happily, bouncing up to 'Sunny Skies' as the disguised Princess climbed onto the station platform. "You made it!"
She threw her hooves around the surprised pegasus, nuzzling up against her chest. "I missed you so much," she said in a trembling little voice, staring up at the larger pony.
"Whyyyyyy?" moaned Shining Armor, burying his face in his hooves.
Celestia's lips curled back from her teeth. She shoved the smaller unicorn away, a shimmer forming in the air where her horn should be as she prepared to erase Nightmare Moon—and possibly a good portion of Ponyville—from existence.
"Oh! Excuse me."
Celestia's rage was interrupted as a mare bumped into her. This new pegasus wore a saddlebag on her back, with a lavender-colored flower as her cutie mark. Her coat was a deeper purple, and her mane, worn up in a complex braid, was light blue, shot through with darker streaks.
"T-that's quite alright, miss…?" Despite her earlier anger, Celestia recovered quickly, defaulting to politeness.
"Lavender Blossom, ma'am," said the pretty little mare, with a dimpled smile and quick half-curtsey. "I must say, it's surprising to see royalty such as you here today, Princess Celestia."
"Well, my duties often require me to travel to many parts of Equestria—" It took a moment for Celestia's brain to catch up with her automatic Princessly response, and she halted, struggling to understand what had just happened. "What… how…"
She blinked, staring at the smirking pony, and then leaned closer. "…Ka-klack?" she ventured after a moment.
"In the flesh. Well, the pony flesh," Lavender Blossom replied, and her grin widened. "Seeing through someone's disguise isn't quite as funny when you're on the receiving end, is it?"
Celestia stared at him/her for a long moment, then finally blew out a breath and laughed. "Alright, you got me," she said, shaking her head. "I'm going to remember this, though."
She took a closer look at the disguised changeling, who showed no shame in preening and parading around. This close, she found the imitation uncanny; 'Ka-klack' was, for all intents and purposes, gone, and a new pony stood in front of her.
"Your disguise is impressive," she admitted after a moment. "Do you… ah, transform like this often?"
"Oh, Lavender Blossom is an old character," replied the changeling nonchalantly. "Comes from a well-established family in Appleloosa. She travels a lot, too, so she can come and go as she pleases."
"Wait a minute…" said Applejack slowly. "Lavender Blossom… from the Bloom family? Lavender can't be a fake! Her ma, Lily Bloom, used to foalsit me and Braeburn—"
Applejack stopped, staring at Lavender with wide eyes, and the changeling smiled sweetly. "You were such a good little filly. A tad rambunctious, though. Why, when I remember the trouble you got into at the Saddleback's ranch that one time—"
"Okay, okay, that's fine," said Applejack nervously, backing away. "No need to go diggin' up a bunch of old messes."
She paused, then, blushing, said, "But thank you for all the candied apples."
"Shucks, warn't nothin' but a little down-home cooking, sugarcube," replied Lavender with a wink.
"That's not exactly what I meant," said Celestia slowly, and the changeling turned her focus back to the Princess. "It's just… do you often… I mean, normally you're a…"
She trailed off, then decided to just drop the subject. The changelings were a race that, with one exception, seemed to be comprised solely of males. Or at least they seemed to have mainly male characteristics; she'd never exactly had any reason to find out how far those characteristics extended, anatomically speaking. Considering the number of mares compared to stallions in Equestria, in order to feed… well, Ka-klack seemed happy enough as either a male or a female, so who was she to question him? Or her?
"I just wanted to make sure you were okay using this disguise to sneak us into your hive," Celestia said instead. "There is some risk of discovery bringing in outsiders, however careful we are."
"No worries," said Ka-klack, with a shrug. "There are, um… precautions, around the hive. Enough to deal with anyone who might come wandering around."
"I get the feeling I may not approve of these safety measures," said Celestia dryly, staring at the mare with lowered eyelids.
"Um… how do you feel about memory-wiping spells and strong suggestion charms?" she asked weakly. "Maybe… a deathtrap, or two. Only deep in the hive, I swear…"
"Not happy," Celestia growled, the let out a groan. "But not surprised, either. And in theory, at least, that kind of thing won't be needed anymore. So, once again, I will forget I heard anything."
She gave a long-suffering sigh. "The things I do for my sister…"
Eyes closed as she sighed, Celestia missed the look Nightmare Moon gave her—one filled with surprise, and a deep sadness, but mostly with an unimaginably furious rage.
"Now that we're all here, there's just one last thing to take care of." Celestia reached back with one wing, fumbling around until she was able to pull a scroll out of her pack. She unfurled it, and the gathered ponies gasped as one as a brilliant golden light shone out of it. The only pony that didn't look on in awe was Nightmare Moon, who shuddered as though her skin crawled everywhere the light touched it.
"This scroll bears my personal magical signature," Celestia explain, rolling it back up and presenting it to Applejack. "It is undeniably from me, and its orders are not to be questioned. Present it to my Royal Advisor. He will take care of ensuring you five are given the powers and authority you require as my regents, and will come up with a suitable cover story as to why you need said authority. Something about my needing a few personal days, perhaps. Or maybe giving the 'Heroes of Equestria' a bit of leadership experience."
Applejack reached out and, hesitantly, took the scroll. "If you're sure about this…"
"I am," Celestia replied softly, with a nod of her head. "I place my trust in you now, as I have so many times in the past."
"Alright, then, Princess. We won't let you down," said Applejack, and gave a bow. Her other friends gathered themselves up and bowed as well, giving their own chorus of agreement to Applejack's statement.
"I know you won't," said Celestia, returning their bows and then heading towards the train with a last wave of her hoof.
"I was just thinking…" Shining Armor said hesitantly, as they waited in line to board behind the other two. "What happens if somepony wonders why the Prince of the Crystal Empire is wandering around Equestria? I know I can't do the whole transforming thing you three can, but don't you think I should have some kind of disguise? Or at least a cover story?"
"I doubt anypony would recognize you on sight," said Celestia breezily, then giggled at Shining Armor's expression. "Alright, alright, just kidding. Here…"
Her wing reached back, digging through the saddlebag again, then came back out and plopped a pair of dark sunglasses and a hat on Shining Armor's head.
"There," Celestia said with satisfaction. "Now you're completely incognito."
"You can't be serious."
"Didn't you ever wonder how I used to sneak out of the castle whenever I wanted to run a few personal errands?" asked Celestia slyly, glancing sideways at him. "Despite you and your guards knowing about Sunny Skies?"
"That's not…" Shining Armor trailed off. "Really?"
Before Celestia could respond, there was an explosion from in front of them.
"You want me to give you a ticket to ride this train?!" shrieked the small Nightmare Moon at a stunned conductor. "This is MY train! The tracks it rides upon belong to ME! This KINGDOM belongs to—"
"Okay, let's all calm down here," said Celestia hurriedly, placing a wing upon Nightmare's back and shifting the unicorn slightly to the side. She pulled a pair of tickets out of her bag and handed them to the still slightly shell-shocked conductor. "I'm sorry about that, the little one hasn't eaten yet and she gets cranky when she's hungry."
"Ah, say no more, ma'am," said the conductor, with a smile and tip of his hat. "I've got a few daughters of my own, and I know how they can get."
"You DARE—" Nightmare Moon's lips started to curl back in a snarl again even as Celestia tried to usher her aboard the train.
"Come on, let's go find you a snack," said Celestia brightly. "I'm sure you'll feel better once you've had something to eat, Moony."
"Moony?!" cried Nightmare in dismay, and Celestia took advantage of her stupefaction to shove her onto the train.