How long has it been? Thought Celestia. The poor Alicorn had lost track of all the years that followed her sister's one thousand year banishment. Her tail drooped and stopped flowing with it's brilliant polar-light colors, and her mane moved on occasion as the wind howled. She stared up into the sky, at the moon that never seemed to wax or wane, making Nightmare Moon's image a horrible sight she was bound to stare at whenever she looked up. Celestia thought that maybe, just maybe, it was close to one thousand years, and then she could finally see her little sister again.
The grown mare walked away from her window and chose a wide open spot on her balcony to stare at the stars. She didn't know why she did this. The night sky only made Celestia more depressed and cut off from the world.
The Princess thought about times when she and her sister were still together. Still happy. There was Luna's 634th birthday...
"Sister, that is NOT how you eat cake!"
"But Tia..!"
"This is!" And with that Celestia had used her magic to throw Luna's cake onto her face. She had blushed, screamed, and in revenge, she threw the entire punch bowl onto Celestia's head. Good thing it didn't break.
Then came the fateful thought that always brought Princess Celestia tears.
Nightmare Moon was threatening her ponies. She had no choice.
So with the mighty Elements of Harmony and magic of her own, Celestia banished her sister to the moon for one thousand years.
Celestia remembered the rainbow light that swallowed Luna up, and a tear rolled down her face.
"Sister?" a familiar voice called. Celestia automatically perked up.
"Luna! Please, come sit next to me! Isn't your moonlight beautiful?" The Sun Princess chirped. "I raised it for you tonight so you wouldn't be so tired, and-"
"Celestia, we have important things to discuss," Luna said. She curled up on Celestia's bed and smiled. "Then, if you wish, we may 'hang out' as thy subjects call it."
"What is it you want to discuss?" Celestia asked, curling at her sister's hooves.
"Celestia...I'm afraid I cannot keep coming here to see you."
In that moment, Celestia's heart shattered into a thousand bits all over the floor.
"Sister...Luna no!" Tia shouted.
"I do not have the energy up here to visit you as a ghost. A voice mightier than yours has been telling me that there is someplace I must go."
"I said a thousand years, and then you could return! Can you wait no longer?" Celestia whispered, in an effort to fight back tears.
"No Celestia." Luna stood. "My ghost has roamed the moon for 1,999 years in wait."
"That's...that's not right..." Celestia ran a hoof through her mane.
"Because when you banished me to the moon, you didn't say One Thousand Years. You said, and I quote,"May the moon capture you and hold you there for thousands of years.""
"I'll go crazy without you!" Celestia could no longer contain her tears, and they began to flood.
"No! No, you'll go crazy if I don't leave!" Luna countered. "I mean, look at the six ponies that you have entrusted with the Elements of Harmony! The pink one has gotten murderous and kills ponies and turns them into food, the one that's obsessed with clothes is the sluttiest mare i've ever met, the rainbow mare has all-together vanished, the one that does apples only knows the one word, that animal pony is catching ponies and re-naming them and calling them bunnies, and the one you know as Twilight Sparkle has changed her name to Dewdrop Dazzle and walks around like she's as drunk as Berry Punch! And you have done naught to revive the friendship among the six ponies because you only await the fate you thought you had given to me."
Celestia was finally defeated, as she found nothing to say.
The day was growing young. The sun would have to rise soon.
"I'm going to leave you, tonight, and never see you again." Luna got comfortable next to her sister. "But it's been over One thousand years, and I still love you, sister. I forgive you, and I will always remember you."
For the next few minutes, the two mares bawled into each other's manes.
At exactly five o'clock, Luna stood for the last time. Celestia watched, tears still falling, as Luna walked onto the balcony. With all the energy she could muster, Luna began to lower the moon.
Just as the moon was on the horizon, Luna collasped.
Then, a miracle.
Celestia ran over, horrified to see her sister's mane glowing a brilliant white. Then her torso. The glow continued to swallow Luna.
"Luna, what's happening?" Celestia cried. But she already knew.
"I love you, big s-s-sist..."
And with the stutter of her words, Luna was gone. Gone with the voice mightier than her own.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Celestia looked at the moon that night, but differently. Nightmare Moon was gone from the moon's surface, and in it's place was what Celestia decided was a heart.
Looking upward, Celestia quietly whispered, "I love you too, little sister."
Celestia was running. She was running through the streets of PonyVille, not bothering to stop when somepony showed their concerns. Finally, Tia reached her place of destination: a large tree house in the middle of the village. Using her horn's magic, Celestia levitated six objects in front of the door. Reaching out a shaky hoof, Celestia tapped the door ever so slightly.
The mare that opened the door didn't LOOK like a Dewdrop anything.
"Twilight...?" princess started slowly.
"Yes...?" Twilight replied just as slowly.
"Oh thank Goodness. I've heard rumors that you called yourself Dewdrop and became something of alcoholic.