Twilight's flight home had been fraught with nerves, and not because of the fact she was sitting in a metal tube going twelve thousand miles per hour, hurtling through the heavens with an inch or two of titanium skin between her and a terrifying death. She had fully expected a team from the ASU to meet her at the Orbiport when they landed.
Is this your pet, miss?
Were you aware he could talk when you purchased him?
I see. Come with us, please, miss.
There had been nothing. She waved her identity card at the half-asleep Pegasus manning the security desk (no need for a cyber-stamp as it had been a domestic flight, not one to the Degenerate Zones. Once she had collected her bag, she simply stepped into a VTOL pod and headed to Rarity's apartment.
Both Rarity and Spike were glad to see her. Spike ran to her and gave her a hug, while Rarity just seemed relieved to not have to harbour an illegal creature in her home any longer. She didn't dislike Spike. In fact she had not had any issue looking after him, nor had he caused problems with her cat. But he talked, and that meant he was wrong, broken. And that, in turn, meant that Rarity was scared.
"It's not that I don't understand why you did it, darling," she told Twilight. "But I just don't...I don't understand why you felt like you needed to."
Twilight had tried to explain, in a way that did not make her sound like a subversive. Having a talking dragon, why, that was just something she had imagined from when she was a foal. There were talking dragons (probably) out there in the Degenerate Zones, and if there weren't now, there certainly used to be. So why couldn't she make Spike talk? Why shouldn't she?
Even as she talked, she knew she was doing it as much to justify it to herself as to justify it to Rarity. She wasn't even convinced she knew why she had done it, in truth. Not if she really dug down deep and tried to analyse her actions. Nopony had told her to do it. Nopony had suggested she do something similar. Nopony had said it was ok to feel that way. She knew it wasn't. Not really. After all, everypony was happy and content, why would she want to risk any kind of problem by trying to be deviant?
She could have done something else if she was feeling adventurous. Something less likely to get her in trouble. Maybe have three stallions (or mares) at once, or singing a ribald song in public, or even hacking a VTOL pod and taking manual control (it had been done before, though it rarely ended well for the would-be pilot). She may have received a telling-off, a slap on the wrist, but that was all. If her adventure was of a sexual nature it would have been entirely ignored, for that was not really an adventure, but merely a part of life.
But she had done none of those things. She had decided to have a pet that could talk and was intelligent, and that had led her to develop a disturbingly insatiable desire to learn the origins of banned words. She had never had that urge before. As far as she knew, nopony ever had. Why would they? The words were banned not arbitrarily, but by the Princess herself, and enforced by the State. That was enough for everypony to know they were bad, bad words. Worse than insults, worse than profanities. They were heretical, anathema to a functioning society. Everypony knew that. Twilight knew that. And yet the curiosity of a young, talking dragon had started her down a path she had no desire to be on.
Taking Spike with her, Twilight had returned home, relieving Rarity of the worry about having him in her apartment. Twilight had apologised profusely and promised to make it up to her somehow. A little nagging voice kept telling her that wasn't enough, that Rarity would sell her out, but she dismissed it. Rarity was her friend. Her best friend and sometimes 'bedroom-friend,' as Spike put it. She wouldn't do something like that. Twilight was sure of that.
Almost sure.
Sure enough to go to sleep that Even-Day at least, with Spike in his basket and thoughts of the unknown Princess on her mind. Her curiosity was driving her, her emotions pushing her forward down the potentially dangerous path she now found herself on.
"My loyal subjects. Your thought for the day. An open mind is like a fortress with its walls unguarded. Perfidious thoughts can invade your head if you are unwary."
The unhelpful message from Celestia, broadcast by the public speaker systems, dogged Twilight as she made her way to the observatory once more. It was a coincidence, of course. She had heard that message dozens of times before during her life. In fact the more she thought about it (despite the message reminding her she should not), the more she realised that Celestia seemed to have a fairly limited vocabulary, for her messages would repeat and repeat, month after month, year after year. They were good messages, of course, useful and absolutely true, but still...the more one heard the same oft-repeated words, the less impact they had.
That was why it was good to find new words, she mused. Even if they are banned.
Moon.
Night.
Princess Luna.
But, why, why, why?
The archives of the observatory had become a second home for the curious mare, a repository of knowledge both modern and arcane. There were hand-sketched drawings from ancient times that had her in guffaws of laughter, so impossibly inaccurate were they. Some showed the Sun orbiting the planet, some showed the planet orbiting what appeared to be a gigantic dragon, and some even showed half a dozen other imaginary planets apparently moving in tandem. They made her giggle with giddy pathos at the sad attempts to describe celestial mechanics, though she approached the issue with far more knowledge than the ponies lost to time who had drawn those scribbles.
Orbiting a dragon? Now that would be interesting. Absurd, but interesting.
Yet she also knew that the sun (along with everything else in the solar system) orbited the galactic centre, a supermassive black hole of immeasurable attractiveness that kept the stars in line, so to speak, just as Celestia guided her ponies along the correct paths. They all orbited her, as the planet orbited her sun, as her sun orbited the galactic centre, and as the galaxy orbited...well, nopony was quite sure of that. It was one of the big questions of theoretical cosmology. The universe was expanding, constantly, in all directions, at a steady rate. In a paradox that would confuse many, it had no true centre. There was no single identifiable point around which the entire universe rotated. The galaxy probably orbited something, but astronomy had not yet been able to identify what that was.
It was an open question with essentially no significance to the average pony in the street, but Twilight wanted to know. She wanted to know everything. How did the universe begin? How will it end? What will happen in between? A good scientist is infinitely curious, she had once been told by a professor at the university. But only about science.
Twilight was finding herself perilously close to diverting from that solid, stable path, for she was finding herself becoming curious about things that did not matter. Things that were troubling, things that she was not meant to be asking, and until Spike had expressed his own childlike naivete about them, things that she had no desire to know. That was changing, she knew, as she rummaged through yet another dusty box of unread documents. She doubted some of them had seen the light of Celestia's Sun (or the artificial light of a gently thrumming fluorescent lamp) for centuries. Even the boxes they were packed in were ancient, half-rotted, tied up pathetically with string that struggled to hold together.
Yet curiously, Twilight now remembered something from her first visit. These time-faded boxes, the ones that looked like they would hold the answers, were not where she had found the messages that mentioned Princess Luna. These boxes contained only tattered remnants of the dreams of long-dead astronomers and mages, proven to be verifiably false by the relentless advance of science centuries ago. Those letters she had found were in a modern box, though a box that contained old papers, orbital diagrams of the Co-Orbital Body. Inaccurate ones, too, come to that. No use to anypony except for curiosity. More accurate records would have all been digitised and stored in the computer banks of the observatory, but not those. They were simply wrong, badly drawn, perhaps by a shaky hand or one not well-versed in such things. Horribly inaccurate. Pointless. Stored just for posterity, but a good place to tuck away something somebody didn't want to be found.
The records were clearly kept for completeness, hence why they were in a modern metal storage box like all the other endless copies. An entire shelving unit had been dedicated to orbital records, some accurate, some not. There were more accurate records from five hundred years ago, so these error-strewn papers must have been kept just as a curiosity, like so many documents in archives often were, just waiting for somepony to dig them up and find out some interesting historical titbit or other. Most would never be looked at again once they were archived, however, and that was why Twilight now realised her mistake. She was looking in the wrong place. If somepony wanted to remove any record of Moon or Princess Luna, the first place they would search would be the old documents. Though the diagrams where she had found the letters hidden were very old, nopony was likely to dig through stacks of inaccurate drawings that did not even have any words on them. They might flip through the first few, realise they were worthless, put them back on the shelf and ignore them. Clearly whoever had been assigned to archive them had been less than thorough in their task, because even if the letters she had found had not contained any forbidden words or names, they still would not have belonged in with the detritus of incomplete diagrams. Evidently whoever wanted this name hidden from view had done a good job of hiding them, and whoever wanted this name to be erased from history had not quite succeeded in their task.
Twilight returned to the racks of metal boxes that held the records, opening them, looking for inaccurate old drawings. She found some in the fifth box she tried, from some three hundred and fifty years ago, when ponies really should have known better. Perhaps they were drawn by some novice, a young apprentice astronomer with a nervous hand and a loud, angry teacher. Whatever the result, they were all but useless from an astronomical perspective, but might they conceal clues for her?
Rummage, rummage, rummage. Page after page, repeated diagrams of the same cycle, the same month. Nothing, nothing...yes! Something! Another letter, incongruous among the endless chaff of illustrations. With clammy hands she seized upon it, brought it out into the light, examined it, inhaled it, read it.
Mage-Astronomer Deep Frost,
I write to you in the hope of confirming that which I believe to be true. I cannot, of course, say too much in this letter, which is why I wish to meet with you. Plotting is afoot, I am certain of it. There is a quiet fear in the air within the palace walls and I am troubled deeply by it. As one of my most loyal and devoted subjects, I have no doubt you shall choose to be on the correct side when trouble does begin. If you meet me tomorrow at midnight outside the southwestern postern gate, I shall know for sure.
Her Royal Highness,
Princess Luna.
Intrigue! Intrigue in the palace, though which palace remained an open question. Twilight still could not quite grasp what she was reading, documentation of an ancient time that seemed to have no record anywhere else. Somepony's fiction, perhaps? It could not be, for typing the name of a fictional character into the public terminal would not have summoned the police. No, this had to be real. It had to be. Princess Luna must have existed once, but where was she now? Her name had fled from reality, as though she never existed in the first place, or had been sucked into the black hole at the galactic centre. These letters were the only places Twilight had ever encountered her. And Midnight, too! A variation on a profanity. Perhaps that was what they had once called Even-Noon?
Carefully, she folded the letter and placed it in her satchel with her textbooks and data-pad, secreting it between two pages of 'Advanced Celestial Mechanics Volume III: A Comprehensive Guide To Planets, Stars and Space Phenomena.' She decided now to retrieve the other letters too, the ones she had read before. They were stored in her textbook as well. If only she could know more!
The following week she returned to the observatory again, and excused herself to the archives to continue her research on orbital diagrams and the recession of the Co-Orbital Body from the planet. Again, she made a discovery, another letter in another box, as though somepony from history wanted to weave a narrative, but simultaneously make it extremely unlikely anypony else would ever be able to read it in full. This one was in a different hand, though written in similarly flourishing style that made it difficult to read. How grateful it made Twilight for computers, where everything was clearly spelled out, pixel by pixel, no distortions and no difficult penponyship.
Mage-Astronomer Sky Chaser,
Please accept my warmest congratulations on your appointment as Chief Astronomer of the Royal Canterlot Observatory. I am sure you will continue the century-long tradition of excellence in such a fine and important institution (your predecessor notwithstanding). Funds for the rebuilding of the observatory will be released to you as soon as I am able to do so. As I am sure you are aware, the Treasury is rather depleted after the war and many other priorities cry out for its attentions. In the meantime, salvage whatever you can from the old structures that may aid you in the construction of the new. I look forward to attending the opening ceremony of the restored and resplendent observatory in due course, and to working with you on establishing a new understanding of the heavens.
Her Royal Highness,
Princess Celestia.
Twilight trembled a little. Was this really the hand of the Princess herself? Did she truly write this letter centuries ago? Remarkable, absolutely remarkable! Almost nopony ever actually saw the Princess, yet here she was holding a letter she had written. Not typed on a computer, but written, with ink and quill and her own elegant hand! But why, why did nopony date these letters? Twilight found herself more confused than ever. Which war was Celestia speaking of? The Great Unification War? The Discordian War? Another war she was not familiar with? Some foul event had destroyed the observatory, it seemed. Perhaps the Chief Astronomer would know more. Perhaps he would even know of his predecessors. But that was tempting fate, Twilight decided, scolding herself for such a thought. She could hardly casually raise the subject with him.
Instead she searched and searched, every box of orbital diagrams she could lay her hands on. But she found nothing. There were no more letters. The letter from Celestia, it seemed, was the last one. Or was it the first one, chronologically? Somewhere in the middle of the sequence? She could do no more at the observatory. Instead, she would try the Royal Academy of Equestrian Sciences, mentioned in the first letter she had found. Yes, perhaps she would find more answers there.