Luna sat in her tower, staring at the remaining embers of her dying fire. The door was locked, and the windows were covered. She was supposed to be asleep, as it was very late in the afternoon, but she was not truly asleep or awake. Daydreaming perhaps, or just spacing out.
Her mind was at work as she stared at the remaining light. Darkness would soon consume the room, but Luna didn't care. In her mind, she was not in that room, in that tower, in that palace, or in Equestria. She was in her own realm, where the moon was always high in the sky and she was free. Free from pleasing her sister, from pleasing the ponies. They're either with her, or against her.
It was unwise to be against her.
She walked through the imaginary fields in the starlit sky. Creatures of the night got out of the way of her graceful step as she continued her stroll. She didn't have any idea where she was going, only that something was beckoning her that way. Like an invisible hoof was around her and led her through the field. There was nothing in any direction, with the exceptions of grass and the sky.
The moon was full, in both realms.
She kept on walking. She should have flown up and spotted her destination, then flown towards it. But she did not. Luna walked in a straight line, unknowing where or why she was walking. The stars twinkled in their brilliance, in her brilliant night. It was hers after all, and it was magnificent.
Finally, her destination appeared in front of her. A cracked stone platform sat randomly in the field. Stone steps led to an archway that was positioned in the back center of the platform. Luna stepped onto it and stood in front of the archway. At first, only grassy fields shown through the other side. But gradually, the vision of the grass faded to blackness, and a dark abyss filled the archway.
Luna walked through the archway, into the complete darkness. She was not frightened, or apprehensive, or intimidated. She hadn't been here before, and did not know what was going to happen, but was only anxious as to what awaited her.
As Luna stood in the pitch blackness, small lights began to shine through. The curtain of blackness of lifted as stars were shown. Planets appeared with them, as well as nebulae, asteroids, and other space faring bodies. She looked around in wonder at the scene. What used to be a silent void was now filled with color and light. A voice, not in her head but not outside, spoke to her.
Luna
"Yes" answered Luna.
We have been expecting you
"Why? Who are you?"
We speak like nothing, but appear as everything. We created you and your sister.
"You have? Then why have you called me here, to this place?"
A comet soared by, becoming a fiery mass as it plummeted into the gravity field of a nearby planet.
You are, much beloved by your subjects
"Yes, I suppose I am" blushed Luna.
You have slain dragons, stopped Discord, and many other acknowledgments
"And?"
Your sister. She is still viewed as the...superior ruler
"What are you getting at? She is the sun, everypony sees here and loves her. When I come out, everypony is asleep."
Does that ever get to you?
"Not at all" Luna lied.
Are you positive?
"Well, I am a bit jealous of her. I do all of these things, get credit, yet nopony cares about the night..."
You created the beauty of the night, yet not a single pony takes time to enjoy it
"Yes, that is right."
Perhaps then, you should make them take a look at it
"You mean make night last longer, so when ponies wake up they can see it?"
Not exactly
"Then what?"
Your sister's rule has become...out of hand. We never meant for her to rule like this, like a queen over her subjects. We needed her to be a loving goddess, not a cruel queen.
"Cruel? I think you have her mistaken-"
She put that rebellious pony to death
"But I was there, and I ordered it. I reminded her of the law."
But she still went through with it. Can you not see that it will not stop there? By reminding her of the death penalty, you sparked a fire that will eventually grow larger and larger. First one pony is silenced, then a thousand!
"Are you sure? I cannot imagine my sister going over the edge like that."
We are all knowing, and we know what will become of her if it is not stopped
"Then what should I do?" asked Luna. "I don't want to see my sister become such a thing!"
Take over
"Excuse me?"
Take over the throne. Not only will you be sparing Celestia, but the ponies will be able to finally see your beautiful night.
"I...I don't know..."
If you do not, your sister will become the tyrant we have predicted
Luna stood there in thought.
"I will do it" she finally answered.
Excellent
"Give me some time, as I will debate on how to go about it."
Take all the time you need Luna. We will be waiting.
Luna turned and walked towards the doorway to the fields. When crossing through, however, her thoughts were stopped and she awoke in her bedchambers. Celestia was standing over her, looking worried.
"Luna are you alright?" she asked.
"Um, yes sister" answered Luna, standing up. "I am fine."
"You don't seem fine" Celestia said. "It's time for the night to begin and you were still sleeping."
"I am fine sister, just a strange dream."
"Okay, I'll be going then."
Celestia flew out of the tower, towards her own bed. Luna's horn began to glow, and the sky was filled with stars and her waxing crescent moon. She looked once more at the fire, now stone grey ashes. All light was gone, and the room was completely dark.
She looked up at the moon, and smiled. Not a smile of joy, or of happiness. Her deviously large smile reflected back at her in the window, so it looked like her face was imprinted on the moon.
And with that, her plans for eternal night were made.