The door to the Golden Oaks Library swung open. Twilight looked up from the book she was reading, a thick tome detailing the thirty-two known types of abjuration magic. Spike was already out running errands, but she was actually rather surprised that anypony else was up and about this early on the day after Nightmare Night.
"Welcome to the Golden Oaks Library," she called cheerfully, "how may I help... you?" Her eyes widened as she saw who had stopped to pay her a visit. A shining white alicorn with a flowing, multicolored mane stepped in and closed the door behind her. "Princess Celestia!"
Twilight flinched back as Celestia turned to gaze at her. Her beloved teacher looked angry.
No. Twilight looked again. The princess was not angry—she had been angry after the Smarty Pants incident, and Twilight blanched at the too-recent memory. No, this was not anger, it was something more akin to disappointment, and somehow that was even worse. Twilight's mind kicked into overdrive, trying desperately to think of the purpose behind this visit. Had she forgotten an assignment? Had one of her friendship reports not been satisfactory? "P-Princess?" she squeaked.
"Twilight Sparkle, we need to talk," Celestia said firmly. Twilight wasn't sure she'd ever heard a more frightening statement in her life.
Twilight sank back onto her haunches, trying to make it look like a deliberate action rather than her legs giving out in terror. It didn't help that she was trembling where she sat. "Okay," she stammered, "um, can I get you some tea? A cushion?"
Celestia levitated one of the many cushions over to herself and declined the tea. "I received your report regarding my sister Luna, and this morning she came to me herself to tell me more about it."
Of the many things Twilight had been expecting, that was not on the list. "Yes?" she said uncertainly. Why did Celestia look upset about it?
"You had her take on the role of Nightmare Moon to frighten the townsponies?"
"Y... yes," Twilight repeated, her ears flat against her head.
"Twilight Sparkle—" Celestia's eyes sharpened, "—you just had my sister relive the most painful memories of her life. She came to me in tears."
The floor seemed to drop out from beneath Twilight's hooves. "But, but she was having fun!" Twilight protested. "Everypony loved it. Why didn't she say anything last night? Oh, Princess, I'm so sorry." Her heart was racing, her eyes filled with tears of panic and remorse. She wondered if she could somehow dig a hole through the wooden floor and pull the edges in after her.
"It is not me to whom you should apologize," Celestia answered firmly. Her voice softened somewhat as she gazed at the mortified Twilight. "I believe that Luna did not bring this up last night because, as you said, the ponies were having fun. She wanted to be accepted, and it seemed to work. I think even Luna was surprised at how strongly she reacted after the fact." Celestia sighed gently. "I know that your intentions were good, my faithful student, but you must understand how badly you hurt her."
"I'm sorry," Twilight repeated, "I never meant to... I thought she was happy... I... I..." Her breath started coming in short gasps as a full-blown panic attack threatened to take hold.
Abruptly, she felt herself wrapped in the downy warmth of Celestia's wings.
"Hush now, Twilight, that is enough." Celestia murmured. "You made a mistake, and as a result you hurt someone you care about. Everypony makes mistakes. What is important is how we correct them."
Twilight threw her forelegs around Celestia's neck and buried her face in the princess's mane. Almost immediately, her heaving sobs eased, then stopped completely. After a long moment, Celestia released her.
"So, how do I correct this?" Twilight asked. Celestia was pleased to see that a hint of the old spark was back in her eyes. She was once again Twilight Sparkle, student of Friendship, and ready to do whatever it took to set things right.
"Speak with Luna," Celestia advised her.
"Of course," Twilight said. "I'll leave for Canterlot at once."
"There is no need," Celestia said. "Luna is just outside. She asked me to speak with you first."
Twilight's pupils shrank to pinpricks. "She's here?"
"Yes. I will get her. When you're done, come meet me at Sugarcube Corner. I suspect some sweets will be needed after this." With a wink to Twilight, she departed.
"Twilight Sparkle." Luna stood framed in the doorway, staring down at the shorter Twilight.
"Princess Luna." Twilight bowed down low to her. "I... I can't tell you how sorry I am, I never meant to—"
Luna cut her off with a raised hoof. "I know. And yet you did."
"Please, if there's anything I can do, any way to fix this, just tell me."
Rather than answering, Luna shut the door behind her and walked past Twilight, farther into the library. After a moment of silence, she turned to face the unicorn. "Twilight Sparkle, do you understand why I was upset?"
"I had you relive your time as Nightmare Moon," Twilight said softly. "I thought it would help you get into the spirit of things. I never even thought of what Nightmare Night must really mean to you."
"Nightmare Night," Luna turned the phrase over in her mouth. "A night of fun and festivities in the name of my darker self. A time to... how did your friend phrase it? Giggle at the ghostie?"
Twilight nodded, wondering where the princess was going with this.
"When I surrendered to the Nightmare, I attacked my sister. Had I succeeded in my endeavor, I would have slain her and doomed Equestria to eternal darkness and cold. A world forever shrouded in night cannot sustain life. Do you understand this, Twilight Sparkle? I would have killed every living being on the planet."
Twilight's stomach twisted. She thought she might be sick, but forced herself to keep listening. Luna was baring her heart, and Twilight was determined to hear every word. Somewhere in there would be the clue she needed.
"When my sister turned the Elements against me, I was trapped in the moon for a thousand years. Have you any idea how long a thousand years is? For fifty times as long as you have been alive, I was imprisoned in a place with no warmth, no food, no air, and no friendship. For a millennium I had nothing to sustain me but my own anger and sadness."
Twilight clenched her teeth and fought against tears. Poor Luna. The emotional trauma from a thousand years of isolation would have to be immense. Just the echo of that pain was overwhelming; it was amazing that the princess could even function.
"Now, I find that all of this has been turned into a lighthearted celebration amongst the ponies of Equestria."
"Princess," Twilight choked, "I... I don't even know what to say."
Luna's attention snapped back to the distraught unicorn and she gasped. "I am sorry. I should not have laid so much on you at once."
Twilight shook her head, a tear breaking through her defenses. "Don't apologize, Princess. I'm the one who needs to apologize. To have all of that thrown back in your face, and then—then I suggested—"
Luna shook her head. "As off-putting as it was, it is... good, I think, that this has become a thing of joy and happiness for ponies. As you say, it was fun." That word still seemed to come awkwardly to her.
Now Twilight was confused as well as horribly sad for Luna. "But Princess Celestia said—" she cut off, unsure of how much to say to the alicorn before her.
Luna sighed. "Ah, yes, my sister can be rather protective of me," she replied. "You see, I am of two minds about last night's festivities. I am pleased to have spent time getting to know my subjects, to have had fun with them. What is more, I do truly believe it a good thing that they have learned to laugh in the face of their fears. As you know, I at first took the celebration as an insult. It took you to show me otherwise." Her mouth turned down again. "On the other hoof, experiencing all of that, and once more taking on the guise of Nightmare Moon, unsettled me in ways for which I was not prepared."
Twilight took an uncertain step forward, instinctively reaching out a hoof toward the princess. She stopped shy of actually touching Luna, but the gesture did not go unnoticed.
"It is alright, Twilight Sparkle," Luna said.
Twilight wasn't sure whether she meant that it was alright to hug her, or that what had happened on Nightmare Night was alright. Luna answered the unspoken question by stepping forward and lifting her own hoof. Twilight immediately wrapped her forelegs around the princess of the night and held her close, as Celestia had held Twilight not long ago.
"I'm sorry," Twilight repeated, doing her best not to blubber into Luna's mane. "I'm so sorry. If there's any way I can help—"
Luna hummed, perhaps not happily, but contentedly. "You have helped already, Twilight Sparkle. Perhaps all I truly needed was someone to talk to. Someone to understand my perspective, as you helped me to understand yours. Nay," she corrected herself, "not merely someone. I needed you to understand."
"Me?" Twilight asked. "Why me?"
Luna stepped back from Twilight's embrace. "You freed me from the Nightmare, and for that I am forever in your debt. When you saw me struggling to fit in with the townsponies, you alone approached me and did your best to help." She smiled. "Your advice was good, and I continue to follow it."
"I did notice that you haven't knocked anyone over with your voice today," Twilight said with a half-hearted giggle.
Luna chuckled. "Indeed, I see that the Royal Voice is no longer suitable for interacting with my subjects. Since my return, you have aided me more than anypony save my sister herself. You are kind, patient, and understanding, and I suppose that is why I needed you to understand this."
"I do understand," Twilight answered. "I'm glad you came to me with this, Princess." She had a feeling that she would spend a great deal of this night crying for Luna and what she had endured, but that was not a problem for here and now. "If you ever need to talk—about anything—I'm here."
"And I appreciate that, Twilight Sparkle. Celestia is as warm and loving a pony as one could imagine, but just a sister is not always enough."
"Well, you have friends in Ponyville," Twilight assured her.
"Indeed." Luna smiled. "And at the moment, I also have a sister in Ponyville who is likely to make herself sick if we leave her unattended at the bakery for too long."
Twilight laughed at that image, but quickly sobered. She just needed to ask. "Princess Luna... do you forgive me for last night? For convincing you to pretend to be Nightmare Moon again?"
Luna's tone turned serious again. "Yes, Twilight Sparkle. It would be a lie to say that I was not hurt, but I do forgive you for it. It was not your intent."
"No, never," Twilight said. "I would never hurt you intentionally."
Luna graced her with a smile. "I know. Come, Twilight Sparkle, no more of this. There is cake to be had."
The cake was eaten, the princesses departed, and Twilight did indeed lie awake for some time that night crying for Luna's sake. Under Spike's clumsy but loving care, she eventually cried herself out and fell into a deep sleep.
She was not prepared for what happened next.
Luna visited her dreams and brought them back to Nightmare Night. Through Luna's magic, they relived that day from the moon princess's perspective, and at last Twilight truly understood. Luna was showing her that, in spite of everything, she had enjoyed the celebration as well as Twilight's company. Luna was using her magic to show that she was alright, and that the unicorn was forgiven for what she had accidentally done.
Twilight, who had gone to sleep in tears, awoke with a smile.
