"THERE CAN ONLY BE ONE PRINCESS OF EQUESTRIA!" Luna shouted as she lept down from the wreckage of her sister's throne. "THAT PRINCESS IS ME!" With those words, she stomped her hooves to the ground and as she did, a dark power started to rise up, slowly transforming her into a mare of evil and darkness. Luna was no more. She had become nightmare moon.
"Luna my dear sister! Please listen to me!" Celestia stepped forward. "It doesn't have to be this way! We were brought into this world to rule together! To keep harmony! You still have a chance to come back from this little sister!" Just then Nightmare Moon lept into the sky and flew down upon Celestia firing dark magic beams from her horn.
"I'll never rule with you and long as those ponies are basking in YOUR sun! Equestria will learn what it is like to have eternal night! No longer will they worship your sun!" Celestia flew away as Nightmare Moon gave chase. "I'll never lower the moon again! Equestria will forever worship my night!" She said laughing manically. Just as Celestia rose to the air, she was hit by a magic beam and she fell from the sky, crashing into the castle below.
"Aahhh!" She hit the ground breaking a wing but otherwise suffering no damage. It was then she lit up her horn as a group of stones rose out of the ground. "I will not fight you Luna! However this is your final warning! Turn back from this, or else!" Nightmare Moon landed and smirked at the injured Alicorn.
"Luna is present no more. I AM NIGHTMARE MOON! RULER OF NIGHT TIME ETERNAL! NOW, IT'S TIME TO FINISH YOU OFF ONCE AND FOR ALL!" Just as she was about to defeat Celestia, the stones started to glow. Each beam of magical light transmitting to Celestia's body, healing her injuries.
"Very well sister, maybe some time alone will teach you a lesson!" As she said this, a powerful burst of magic erupted from Tia's horn, aimed right at Nightmare Moon, who was caught off guard as it hit her square in the chest, sending her right to the moon.
"NOOOOOOOOOOOO!" She screamed as she hit the moon, the shadows taking the form of her face. Just then, Luna woke up screaming.
"NO SISTER WE ARE SORRY PLEASE DONT SEND US AWAY!" She said crying. "WE ARE SORRY!" Celestia woke up and coughed as she looked at her sister.
"Luna it's okay.... You were having a nightmare... Are you alright?" She looked at her with a worried expression. Luna hugged Tia and sobbed.
"I had that dream again... About when you banished me... I... I hated being alone. If you die, I'll be alone again..." She said sniffling. Celestia smiled and wiped her sister's tears away.
"Luna help me up... I need to show you something..." Luna obeyed, and helped her sister stand. "Let's go outside for a moment..." She said as Luna wheeled her life support machine with her. As the two sisters made their way out to the balcony Celestia opened her wings and stretched, wincing a bit.
"Look out in the horizon... Everything out there.... The land, and it's inhabitants, are going to rely on you for leadership and protection once I die..." Tia explained. "With a numerous amount of subjects to watch over, you'll never be alone..."
Luna started to tear up again. "But without you sister, how will I know what to do?..." Celestia merely smiled and hugged Luna weakly.
"Luna.... No matter what happens, I'll always be with you in spirit... Now... I need to lay down.... Why don't you start preparing the night?" Celestia said as she coughed.
Luna smiled and rose to the air. "Very well sister.... I even have a surprise for you too!" Her horn lit up, and the moon started to rise. When it was at its peak, her horn flashed once more, and the sky erupted in waves of color. Aurora Borealis was the correct term in Twilight's book. The spell was simple enough, however it lasted only ten minutes. Long enough for her to show Celestia.
"Sister! Sister come look! Look at the surprise I made for you!" She flew back into her sister's chamber smiling excitedly. But soon her smile faded away as she found her sister slumped over the edge of the bed, the life support machine reading zero. "S-sister?..."
Luna made her way over to the bed and felt Celestia's vitals. There was no response. She wanted to scream for help, and try to revive her, but as she was about to, she noticed a piece of parchment next to her sister's body. Luna picked it up and read it.
"Dearest Luna,
If you are reading this, I am gone... But please do not weep for my passing... Instead, be happy that I am no longer suffering and remember all of the good times we had together... I've been through a lot in our time apart... I've lived my life to the fullest, and now it's time you live yours. I wish nothing but good things for you in the future. No matter what, I'll always be watching over you.
Love, Tia
Luna read the letter again as her tears streamed down her face. She leaned down and kissed her sister on the forehead one last time. "Goodbye big sister..." Then, she lifted her sister's body onto the bed and put her into a respective position. Then when all was said and done, she looked outside to see that her spell had faded away. Now only a starless night sky remained. After a few minutes of staring, Luna collapsed in the floor and sobbed.