Meanwhile…
Luna stood vigilant on her balcony, as she had every night from dusk until dawn with her green eyes slowly and methodically scanning the heavens. Her sentinels stood silent in the dark corners of her quarters with a degree of alertness surpassed only by Luna herself. They acquitted themselves well to the circumstances, such loyalty is not unappreciated, she thought to herself. If only we were all so strong.
Luna had been made aware of Celestia’s plan to reform Discord those many days ago, though she had not agreed with it. But in the end it was her decision to make, and Luna didn’t begrudge Celestia’s choice when it went against her recommendation. The princess of the night had retired for the day and had managed to sleep blissfully for several hours before the effects of a powerful spell brushed against her senses enough to wake her. About an hour later her head had nearly exploded as another spell was cast from within the castle.
Luna was wise enough to realize that something was amiss, and immediately galloped to the court chamber to ascertain just what was happening. The court itself was nearing riot conditions upon her arrival, and the fear was clearly apparent on every face there. The petitioners were screaming questions and crying out while the guards maintained order. The royal guard themselves were too disciplined to show it, but fear was in their eyes as well.
Celestia’s Solar Throne had been obliterated, the ornate golden throne and furnishing melted into a pile of slag at the head of the chamber. Several of the banners hanging behind the throne burned and smoldered, and some of the guards themselves looked thoroughly singed. Strangely enough, the one thing that caught Luna’s attention was a half-burnt letter in danger of being trampled by the panicking petitioners. She had telekinetically yanked the scrap of paper off the floor, and her eyes widened as she saw the first three words.
Twilight is gone.
Luna did not have the time to inquire of the origin of the letter before the sun plummeted from the sky, only for it to reappear on the eastern horizon a moment later. The Solar Court descended into pure panic before a shout from Luna drew the attention of the room. And just as order was on the precipice of being restored, Celestia returned.
The sound of her teleport was an order of magnitude louder than Cloudsdale’s loudest thunder clap, and it accompanied a wave of heat and physical force that knocked everypony off their hooves. Luna was the first to recover, and what she saw filled her with a degree of dread she had felt only once before. The power of Celestia’s teleport had ignited the red carpet leading up to her throne, as well as cracking the marble floors beneath her hooves. Each hoofstep thundered all the more loudly for the silence that now filled the court as the petitioners and guards alike saw what Luna dreaded.
Celestia wasn’t angry, nor was she livid. Such words paled in comparison to the expression on her face and the emotion in her eyes. She was wrathful, and magical energy radiated from her like flames from the sun itself. Nopony present had ever seen Celestia in such a state. Nopony except Luna.
“Captain,” Celestia boomed as she approached her guard contingent, “The Solar Court is adjourned. Muster your troops and return here in ten minutes for your briefing. Do not be late.” The guard captain, a unicorn with enough bulky muscle to put most earth ponies to shame, rapidly agreed and galloped away with almost indecent haste. The rest of the room remained paralyzed in horror at the spectacle before the Princess of the Sun swept her godlike glare across them. Without saying a word, the order had been given: get out.
“Luna, we have much to discuss. Prepare yourself,” Celestia ordered, and the two princesses vanished in a burst of golden light to discuss matters of grave importance that were not meant to be heard by lesser ears. That was the public story, anyway.
The sound of her chamber doors opening brought Luna back to the present, and she silently chastised herself for allowing her mind to wander to the past. Thankfully she hadn’t lost her place in the night sky, and she had to force herself not to turn and address the new arrival. A faint whisper filled the chamber followed by the sounds of hooves as two of her sentinels intercepted the interloper. “Princess Luna has asked not to be disturbed,” they hissed in hushed tones.
“Stand down,” Luna ordered without looking back, “I have been expecting this one.” The sentinels wordlessly returned to their roosts and the clip-clop of hooves approached Luna before stopping a respectful distance behind her. “You’ll have to forgive me for not addressing you face to face, per se, Shining Armor. I’m afraid I cannot afford to allow my current activities to be interrupted.”
“I understand, Your Highness,” Shining Armor replied, “Princess Cadance and I arrived in the capitol only recently. She is speaking to the Lunar Court now, so I felt it best to report to you personally.”
“Your haste is appreciated. I can understand that this is an inconvenience for both of you to return so suddenly during your efforts to help the Crystal Empire.” Luna nodded, though her eyes remained locked onto whatever distant point she was surveying while delaying the inevitable.
“We were happy to help in any way we could, though we are concerned. Some of the rumors we’ve been hearing recently have been conflicted, and Twily hasn’t written me back yet,” Shining said, and his questioning tone continued, “I am also glad for any excuse to travel with my wife but I’m not certain I should be here when I could be helping the Crystal Empire prepare for the Equestria Games.
“I’m afraid recent events do concern you, though indirectly.” Luna explained, before swallowing to clear her nervousness, “Sentinels, disperse.” Without a word or moment’s hesitation, the Sentinels took wing and vanished into the night’s sky to leave Luna and Shining Armor alone. “Brace yourself, what you are about to hear may be shocking.”
And so Luna began to retell the tale that Celestia had told her. Discord was to be reformed, and was left in the hooves of the Elements of Harmony. The plan had gone awry when Twilight fell for a trick and vanished. This caused a brief bout of outrage from Shining, but he clamped down on his outburst to allow Luna to continue.
After receiving a hurried letter from Spike and the girls, Celestia had ‘departed’ Canterlot to investigate just what had happened, only to return and muster the guards and assign a garrison to Ponyville before sequestering herself in her quarters to ‘resume the search for Twilight during the daytime hours’ while Luna continued the search at night.
A long moment passed as Shining mulled over the explanation. Luna had just started to panic under the possibility that he hadn’t accepted her retelling of events but was saved by his next question, “And where is Discord? I haven’t heard anything about him breaking loose, and Twily said he was never one for being subtle.”
Luna let out a breath she didn’t know she was holding before continuing her explanation. “Celestia’s quick action ensured Discord’s containment near Ponyville. Without all the Elements I’m afraid he can no longer be petrified in stone, but Celestia devised a clever prison to contain him, and the garrison at Ponyville will ensure the prison will not be met with outside interference. He…refuses to reveal Twilight’s location, or return her to Equestria. He has insisted to this day that she remains unharmed, and as far as my sister and I can determine he is correct.”
The unicorn let out a relieved breath; Luna suspected it was more about the confirmation of his sister’s continued existence than the containment of Discord. “Twily’s safe, wherever she is. Have you been able to find her? Any trace, any lead at all?”
“Celestia continues to search every inch of Equestria that her sun can see, and I search the night skies. As I said, we can still feel her presence. She still lives, though she is very far away.”
“How far away?” Shining asked, disbelief coloring his voice now, “Where could Discord have sent her that the sun can’t reach it?”
Luna considered for a long moment before answering with a question of her own. “Shining, what is Equestria?”
“It’s our nation.”
“And what is our nation when combined with our neighbors, and their neighbors, and the lands beyond them, and the oceans in between?”
This answer came less quickly, “The total of all the nations, lands and oceans make our world.”
Luna nodded again without moving her eyes. “And what of the moon and the sun? What is there when they are all combined?” When the answer wasn’t apparently, Luna smiled and answered herself, “The astronomers call it a ‘solar system’. Tell me, Shining Armor, do you feel that this arrangement of stars, moons, worlds, continents, oceans and nations is unique? That out of all the lights in my night sky, ours is the only one with a star with a world nearby? That our world is the only one with creatures that think and live as we do?”
“…oh.” Was Shining’s only response after a long moment, and Luna had no doubt that he was now looking up at the stars with newfound wonder and appreciation. “So she’s out there, somewhere. How do you know she’s alright? What if Discord sent her somewhere filled with savages and monsters? What if—“
“Shining Armor,” Luna didn’t shout, but for the command in her voice she could have screamed the words. Instantly the unicorn fell silent and Luna could feel his eyes on her, and she struggled inwardly as to what she could say to calm him. “Shining, did I ever tell you how I met Twilight? My dear sweet sister decided the time for my grand introduction to the modern world would be on the holiday celebrating my… darker days,” Luna could hear Shining’s groan of comprehension as the implication for Celestia’s motivation became clear.
Rather than dwell on that, Luna continued, “I arrived in Ponyville to find the celebration already underway, and my attempts to ingratiate myself with the populace were met with apprehension. You were captain of the guard at the castle at the time, you no doubt are aware of the behavior of the staff. My return was... less than welcomed.” The looks of fear she had inspired in her servants still filled her with guilt, but the next part of the story made Luna smile, “Only one pony in Ponyville spoke to me of her own free will, and that was your sister. She helped me more than I dared hope, Shining, and she and I would share the occasional letter of social and scientific nature.”
Shining’s chuckle was heartfelt, “That does sound like Twilight. I hope she didn’t bother you too much, Princess.”
“No, no!” Luna interrupted, and she nearly looked down to Shining Armor but stopped herself, “I worry that if anyone was a bother, it was me. You may not realize this, but she was the first friend I had made after returning from the moon; the first friend I have had in a thousand years. I won’t argue that Celestia has been wonderful but there was always the nature of our previous parting that hung over us; that we had each done terrible things to the other. So much history, so many wounds.”
“But Twilight, dear Twilight, cared not a whit for that terrible past. She cared about me, personally. Not the monster I was, not the royalty I am now, just… me.” A long moment of silence passed and Luna had to resist facehoofing after unloading that many personal thoughts onto Shining Armor. “Forgive me, without Twilight it seems you must bear the brunt of my personal quandaries.”
“It’s alright, Princess,” Shining said, and Luna felt that she could believe him, “Believe it or not, I have a bit of experience dealing with the personal problems of princesses.”
They both shared a chuckle at that before silence fell between them again. “Shining, the reason I share this is because I want you to know why I am searching. I am obligated to search in order to thwart Discord’s plot; I am compelled to search because Twilight is my sister’s student; I will never stop searching because she is my friend.”
“Thank you, Princess,” Shining replied sincerely before turning towards the doors he entered from, “I know for certain that if you are searching, then she will undoubtedly be found.”
“Indeed. One last thing, Shining. What we’ve discussed here, all of it, is to be kept confidential. While I could tolerate any embarrassment about my personal revelations, the nature of Twilight’s disappearance as well as Discord’s return are considered secrets of the state and would cause a panic if publicly known. You may tell Cadance, as she will be working in our stead for public affairs, but no others.”
“I understand,” came the reply, before the door opened and shut.
The moment her privacy was returned, Luna let out a ragged sigh and chastised herself for the number of lies she had just told. When one does not tell the whole truth, it is surely as malicious as a lie.
Upon Celestia’s return, she had teleported herself and Luna into her private chambers. There, the wrathful persona the Princess of the Sun had shown had dissolved into something that had unsettled Luna more than a wrathful Celestia: she began to weep. The erratic movement of the sun had been Celestia sweeping the entire planet for any sign of Twilight, and had come up empty. She had then given Luna the orders for the troops mustering, and their new duties in Ponyville before teleporting her back to the court and hadn’t been seen in public since. She even refused to speak with Luna despite repeated attempts to talk since the incident. Despite Celestia’s shocking polar attitude switch and the news of Twilight’s disappearance, what was probably the most disturbing was Discord himself.
The rampant mayhem that was expected from the avatar of chaos never manifested. Discord was found atop the same hill he had been left on, sitting in a throne of his own conjuration with his paws steepled before him. He had not moved an inch when Luna appeared and questioned, then threatened him. He had not moved an inch when the garrison arrived. He had not moved an inch when Luna had conjured his holding cell around him, nor when the unicorn arcanists inscribed the runes to make the prison permanent. Discord had only responded once when Luna had asked, “What are you waiting for?”
His reply was simple but cryptic, and it haunted Luna's every waking moment since.
“I'm waiting for Twilight to fulfill her end of the bargain.”