Princess Luna, currently having taken the form of Nightmare Moon, flew towards Ponyville at a speed that could be even compared with Rainbow Dash's. She wanted to find Derpy as quickly as possible, but she had little idea of where to begin. Her mind was filled with so many thoughts and emotions, it felt like it could explode at any moment. Nightmare Moon suspected that her sister must have done something else aside from hiding the letter to keep Derpy from returning to the castle. She knew that Derpy lived in the town of Ponyville, as did many of Equestria's citizens, but nothing else.
'Oh, Derpy...where could you be?'
The unicorn pegasus cautiously glided in circles over the perimeter of Ponyville; there was still some hatred left in her heart that prevented her from reverting back to her original form, and if she entered the town as she was, it would undoubtedly cause a massive panic. Nightmare Moon's magically-enhanced vision allowed her to easily scan the area even from a height of several miles above. She saw many ponies that looked similar, but none of them were actually Derpy.
Her heart heavy like a lump of coal in her chest, Nightmare Moon was almost ready to give up. Suddenly, purely by chance, she spotted a certain purple unicorn and her friends huddled together in front of a house. She was instantly able to recognize them as Twilight Sparkle and the other ponies who had utilized the Elements of Harmony and spoiled her scheme of creating an endless night. Nightmare Moon also knew just how dedicated they all were to her sister.
'Those ponies...just what in the world are they doing? Twilight Sparkle is my teacher's most faithful student, and she would do anything that my sister asked of her! All of her friends would probably do the same. Wait a minute...if they'll do anything...then does this mean that my sister asked them to-?'
Nightmare Moon did not even wait to finish her own thought before she evaporated into smoke again. She needed to find out the answer for herself before anything terrible happened.
--------------
Twilight Sparkle wasn't exactly sure how she was supposed to handle a pair of terrorists with a deadly explosive in their possession. Beforehand, she had rummaged through the library's entire archives for any books focusing on the subject, but unfortunately all she found were elaborate tales of fiction about spies or government conspiracies. Thus, she had to gather whatever ideas she could from her readings and make use of them in a real-life situation the best that she could.
"Okay! Applejack, you and I will surround the front entrance! Rarity takes the left side and Fluttershy will take the right. Rainbow Dash, you keep an eye out from the roof just in case!"
"Fluttershy is still unconscious, though..."
"Well, wake her up!"
"I think she's actually asleep now,"
"This is important, Rainbow Dash! Without Pinkie here, we need everypony's help!"
"Alright, just calm down! I'm on it!"
A few moments later, Fluttershy let out a tiny squeak, affirming that she had finally regained consciousness.
"Ready, everypony? Keep your wits about you; we're not dealing with manticores or dragons this time, who never meant any real harm, but actual terrorists! You never know what they might pull! They also have a deadly explosive! Whatever you do, don't let them detonate it!"
"...Ya know," Applejack remarked, smirking to herself, "If ah didn't know better, I'd say you were enjoyin' yerself with all o' this leader stuff, Twilight,"
"I just want to keep Equestria and the Princess safe!"
"Sure, but I doubt there's much ya need to worry 'bout from good ol' Derpy Hooves!"
Twilight sighed; even though her friends were helping her, it didn't seem like many of them could take the situation too seriously because of Derpy's reputation as a goofy odd-ball. Twilight refused to believe that her information was wrong, or that the Princess had lied to her. The unicorn opened her mouth, preparing to tell them how you can't always judge a pony by its looks, when Rarity spontaneously decided to bring up a very good point, a missing piece to their plan.
"Excuse me, darling, but how exactly are we going to get those awful terrorists to come out here and be arrested in the first place?"
"That's a very good question, Rarity! What we have to do is..." Twilight's smile faded the instant she drowned off; she really didn't have a clue. The terrorists had deadly weapons at their disposal (presumably), whereas none of them possessed any sort of actual weapons at all. One wrong move could result in the loss of hundreds of lives. This was definitely not a job for ponies like them in any sense. Twilight stared blankly at the ground beneath her feet, prompting Rarity and Applejack to exchange worried glances.
"C'mon, guys, isn't it obvious?" Rainbow Dash spoke up, suddenly annoyed at her friends' reluctance to act, "All we gotta do is bust in there, and kick some tail! If they have a bomb, no big whoop, just beat them down before they can activate it! If you're all going to act like a bunch of scaredy-fillies, then I'll start off things for you! Watch and learn!"
"Wait! Rainbow Dash, don't do anything hasty just yet!" Twilight stuck out a hoof to her friend, shouting at her. Unfortunately, the rainbow-haired pegasus pony refused to listen. They couldn't stop her when she got like this. Rainbow Dash ran straight at the front door as fast as her legs allowed, flapping her wings a little at the same time to increase her speed even further. She could feel the wind surround her, enveloping her. All of her friends were shouting for her to stop, but their words were drowned out by the gust's roar. Rainbow Dash had to admit that it was a wonderful feeling. 'Speed is the best...there's nothing greater than going fast and leaving the rest of the world behind you-'
Rainbow Dash braced for impact, expecting to tear right through the door itself. However, the door swung open with a bang at the last second, smacking the gutsy pony across the face. She then proceeded to be hurled into a nearby shrub. Fluttershy fainted again. Dr. Whooves stormed out onto the front steps.
"What is going on out here? Who are you ponies and why are you standing around my house and talking so loudly? I'm very busy at the moment, you know!" Dr. Whooves shouted at Twilight and her friends, totally unaware of what he had just done to poor Rainbow Dash. Derpy Hooves peeked her head out from behind the disgruntled stallion; she had just been eating her third muffin in a row when this all happened. Twilight Sparkle, startled by Dash's unexpected defeat as she was, shook it off and put on a brave face.
"Y...You can't pretend that we don't know what's g-going on! W-We were sent h-h-here by Princess Celestia herself to a-apprehend you! You two are a pair of t-terrorists planning on murdering the Princess and taking over E-E-Equestria!"
"...What?" That was all Dr. Whooves could bring himself to say.
"Ya'll better be ready to spend th' rest of yer days in jail where ya'll belong!" Applejack approached the two of them with a long line of rope dangling in her mouth. Dr. Whooves slowly backed away as Applejack came closer and closer.
"I don't know what's going on here, but you're all being incredibly ridiculous!"
Rarity took a step forward. "Bite your tongue, you insidious cur!"
"What?"
"I told you to be quiet! And I think you should do something about that mane style of yours...it's so last season..."
"I like my hair the way it is, thank you very much!"
The argument would have probably gone on for hours, neither side willing to give in, but fortunately Nightmare Moon herself materialized onto the scene. It happened with an explosion of black flames and smoke erupting from the ground, and it all twisted together to form her physical body. This was the last thing that any pony there had expected to have happen, that was for sure.
Twilight, Applejack, Rarity, and Dr. Whooves all shrunk back in silent fear, but Derpy stared up at the demonic-looking horse with child-like curiosity. Nightmare Moon's heart soared in relief at having finally found Derpy, but before they could depart together, she had a few things that she needed to do first. It was now up to her to fix all of the wrongs her sister had committed.
"Twilight Sparkle." Nightmare Moon peered over at the terrified unicorn pony out of the corner of her eye.
"Nightmare Moon? No, this can't be happening! This just can't be! We don't even have the Elements of Harmony to combat her power anymore! What the heck is going on here?" Twilight cried; she had been having a tough day so far, and it definitely wasn't doing any good for her high stress levels. "Wait, you must have been planning this terrorist plot all along, haven't you?"
Nightmare Moon rolled her eyes at Twilight's accusations; her sister had always been terrible at making up lies, even when they were little fillies.
"Twilight Sparkle, I am not here to do anything that would put Ponyville or Equestria in harm's way. Do not immediately think I am up to something sinister simply because of my past misdeeds; I am only here to make things right again."
"Make things...right?"
"Yes. First of all, there is no terrorist plot, and there never was. It was all nothing but a lie made up by my sister to keep Derpy Hooves from coming back to me." Nightmare Moon explained matter-of-factly.
Twilight looked like she had just been told that the library had burned down. "Princess Celestia...lied...TO ME...?" She mumbled the words over and over under her breath as she struggled to fully understand them.
"Not only to you, but to your friends, to me, and to Derpy as well." continued Nightmare Moon.
"Why would she...?"
"I've said enough about it. I don't want to talk anymore. This whole experience today has left me very upset. Right now, I just want to be alone..." Nightmare Moon tried her hardest to keep herself from blushing as she acknowledged the object of her affections, "With the mare I love most of all. Derpy Hooves, will you please accompany me?"
"Er...don't know who you are...muffins is scared,"
"I may look different, Derpy, but it's me...Princess Luna." Nightmare Moon smiled softly.
Derpy's cheeks became flushed. "O-Oh!"
Dr. Whooves, who had been standing off on the sidelines the entire time, arched an eyebrow in surprise. 'This is Princess Luna? Geez...Derpy really won over a looker, didn't she?'
"Derpy, I must speak to you in private. It's...it's very important,"
"...There won't be tomatoes, will there?"
"N-No."
"Okay, I go!"
Nightmare Moon's smog-like mane suddenly seemed to take on a life of it's own, stretching out in all directions as it coiled around both its owner and Derpy Hooves. Twilight shielded her eyes as the extended mane started glowing, and after a few seconds, the two ponies standing before her had completely disappeared. It was almost as if they had never been there at all.
"My, my! This is the first time something like THIS has ever happened, isn't it?" Rarity touched her hoof to her mouth in a display of faint surprise. Applejack nodded.
"Oh, man...my head is pounding like crazy," Rainbow Dash groaned as she rolled out of the bush, "W-What happened? Did I...did I save the day? Am I the hero of Ponyville yet?"
Applejack turned to the speedster pony and smiled sympathetically at her. "Sorry, sugarcube, but that's gonna have to remain just a dream for now,"
"Aww, shucks! I guess I'll have to stick to tricks instead of abusing my new-found fame to get the Wonderbolts to notice me!"
Dr. Whooves was about to retire to his house, tired but still satisfied that Derpy and Luna were now together, when he noticed how distraught Twilight Sparkle was. Learning that the Princess had lied to her had struck a heavy blow to the girl's trust in her mentor. The colt walked up to the female unicorn and patted her on the shoulder.
"Don't feel too upset about it, my dear; even the Princess of Equestria is bound to make a few poor decisions every now and then."
"I'm just still in shock over it, I guess...but if you're not a terrorist, then who are you? I've seen you around Ponyville a few times, but we've never talked."
"You may call me Dr. Whooves."
"Huh? You own a clock store, right? Then...why are you doctor?"
"Oh, I AM a doctor."
"Are you in the medical profession too?"
"No, I'm not that kind of doctor, but I work as a therapist part-time. That's how I met Derpy, although she always pays my bills with nuts and granola bars instead of actual bits."
"Ah."
"In any case, it looks like things are going to be just fine between her and princess Luna after all."
also, pay with granola bars!? why I didn't think of that before! I'm gonna be rich in no time!
They probably won't accept them
Also, be careful of the pre-spoilers:
That numbed the impact of Rarity's because we knew her comment was going to deflate their plan. To me, it would have been better for her to bring it up and then jumped right to Twilight being completely at a loss.
Both problems are forms of over-narration, giving too much detail that's either unnecessary or redundant (plus the timing issues). If you put this away for a week (no peeking!) and then look at it fresh you'll probably see what I mean.
I am still trying to do better at making multiple-chapter stories, and I will try to keep avoiding this mistake. I will need to keep this as a reminder. I hope everything else was okay, though.