Once upon a time, two regal sisters lived in harmony. They ruled with grace and leadership. The sisters loved each other dearly, despite their differences.
But alas, those times are gone.
No longer did they live in harmony. And grace? None. As for their love, the younger sister's withered away, while the eldest's she purposely threw away. The younger sister admitted this fact, and the eldest seemed to accept it. When the young mare asked her older sister if she felt the same way, the older mare refused, burying her anger inside. Then, the eldest proceeded to falsely love her younger sister.
This gave the younger sister false hope.
"Celestia?" Luna called. "Celestia? Where are you?"
Celestia was... dealing with private matters. "One moment, Luna." She replied. When she came down the steps, she asked: "What is it?"
"Oh, nothing." Luna smiled.
"Luna, what have you-"
"Nothing. The question you should really be asking is," Luna smiled even wider. "What have you done?"
"Luna!" Celestia screamed as she was dragged into darkness.
"No.... Stop... Please.... Luna..." Celestia croaked. It was a cold, desolate room. And Luna had kept her sister there for days.
"What, afraid of the dark?" Luna suddenly appeared in front of her sister.
Celestia didn't want to give her sister any satisfaction, so she stayed quiet.
"Why are you doing this?" Celestia begged.
"Don't act like you care. I know the truth." Luna hissed. "You lied to me all these years... and to think..." Her face was gaunt, and her eyes darkened. "I was starting to love you, like a sister should. You are family. So I tried. Oh, I tried. But," Luna smiled wickedly. "Now I know why. You don't love me back. So why should I love you?" She inquired.
"I... I do love you, Luna. I..." Celestia stammered.
"Don't LIE to me!" Her sister roared. "Don't... lie, you little..." She muttered as she trotted away.
"Luna, wait-"
But she was already gone, and the silence began once again.
"Celestia... I want you to tell me the truth." Luna whispered. Celestia was getting quite used to the dark room, and every once in awhile Luna would visit.
"Luna, you know I have been telling you the-" Celestia once again tried to convince her sister. Convince herself. Was her words a lie? Was her whole life a lie? What kind of mare was she, lying to her sister about such matters? What kind of pony are you, not even knowing if your own words are true?
"LIES!" The younger sister shouted.
"If you know it's not true, then why don't you leave me alone?"
"I want to hear you say it. Confirm it. And, if you know it's not true, then why are-"
"I don't know, Luna...!" The elder princess cried. "I don't know... I'm sorry..."
"You're sorry? That's all you have to say? You... disgust me."
"Luna..."
"Do you know what I've been through? Been going through? The nightmares, they... Tell me things. The want me to..."
"To what? Sister, you shouldn't-"
"Don't. Don't call me 'Sister'. You have no right. As for the nightmares, they have proven to be more trustworthy than the likes of you."
Celestia dare not answer to that.
"I will return tomorrow. And I expect the truth."
That happened a decade ago. Having told the truth, Celestia was released, and Luna forgave her. Or so it would seem. After that incident, not another word was spoken of the matter. It seemed as though Luna even forgot about the whole thing. Celestia, however, did not. Every so often she would think about it. How did her sister even find out about her charade? She told herself it was no matter. but then she wondered how her sister could forget...
This troubled Celestia greatly.
She began to watch her sister closely. Celestia noticed something. Her sister had been more and more distant as the days progressed. Luna was spending more time in her room, and Celestia sometimes heard her talking to herself. Or was somepony actually there, invisible to Celestia's eye?
"Celestia." Luna called, her voice unnaturally nonchalant.
Celestia came to her sister's side. "Yes?"
"I've been thinking..." Luna had the same mischievous smile she wore years ago. "An apology is in order."
"For what?"
"That incident years ago."
"Well, go on, then."
"Oh," Luna's smile turned into a sneer. "You must be mistaken. I'm not the one who needs to apologize."
Celestia frowned. "Luna, I don't need to-"
"Hm. Typical Celestia." Luna laughed, but it was far from lighthearted. "Always thinking you're perfect. But you are far, far from it."
"I don't think I'm-"
"Quiet!" Luna was furious. "I've been fighting for so long, dreading my own duty! I used to love the night, now I dread it! Every night, I... I mean they..." She shuddered.
What have 'They' been doing to Luna? Was she talking about the nightmares? Celestia now pitied her sister.
Suddenly, Luna's expression turned from anger to shock. She writhed in pain. Blue smoke encased her.
"Luna!" Celestia screamed.
When the smoke cleared, a mare that did not resemble Luna stepped out. She was pitch-black, with a wild starry mane. Her pupils were thin slits.
"Apologize, dear Tia!" Said the black mare in an eerie tone. "Confess, and you shall suffer less pain!" Her horn lit up, and the room became noticeably darker. The Nightmare slowly approached Celestia.
"Luna, stop!" Celestia hurriedly backed up and tried to defend herself.
"We will not stop until you are taken care of!"
Celestia screamed once more. Black shadows appeared. Their eyes glowed blue, and their smiles were wide.
The Nightmare smiled.
The shadows closed over Celestia, dragging her into blackness.
"Goodbye, dear sister, goodbye!" The Nightmare laughed gleefully.
