Prologue
Canterlot Castle, The Second Kingdom of Equestria
First day after Discord crisis
2 A.N.M.C. (After Nightmare Moon Crisis)
It seemed that no matter where Princess Celestia was in her thousands of years of life, she always had close friends for loyal subjects.
Yes, that had been true for all of her life, all the way back when it was just her and her parents Solaris and Artemis, to the coming of the "Mane Six" and the defeat of Discord.
Celestia looked around the expanse of the inside of Canterlot castle. In the room she was in was where the award ceremony had taken place the day before. Castle staff was still cleaning up from the almost Grand Galloping Gala sized event where 6 ponies, Twilight Sparkle, Rainbow Dash, Applejack, Pinkie Pie, Fluttershy, and Rarity, where all given medals (except for Spike) for the saving of their planet, Equi, from the Tyranny of Discord. They had all worked hard to save their world, and had almost failed at doing so, but had all ended up succeeding based on the bravery on everyone of them, including her faithful student, Twilight Sparkle.
"I was just a student of magic once." Celestia reminded herself reluctantly. "Yes, never mind that I am a princess now and the twin head of Equestrian government, it was once just a young venerable filly who didn't know her right hoof from her left hoof." Celestia whipped her mane. "And I always had my friends too. Good friends, kind friends..."
Celestia looked up at the sun and thought bitterly, "Dead friends, gone friends, friends that-" Princess Celestia stopped herself. "No, I will not allow myself to go back into that mindset, I refuse. Today is a happy day, it ought to be about happy things. Although-" She looked out into a courtyard outside of the large ceremony hall, a local sundial read around midday with it's shadowy arms.
"Today might be a happy day, but that does not mean that it cannot be a day of respect." The Princess told herself.
Princess Celestia made her way out of the ceremony hall. As she passed through Canterlot Castle's anterooms and halls, she was reminded of the rooms and expanses of Gallopia Bastion in the First Kingdom of Equestria. The old Bastion's rooms would have easily dwarved the rooms found in Canterlot Castle a hundredfold.
"And to think I still remember that old castle even thousands of years later. I mean, well, I am an Alicorn, so my memory is better than that of a normal pony, but I can still remember..." Celestia started to reminisce. "It was such a beautiful place. My mother and father told me that the original structure predated both of their births. It had many a royal garden, and the guards were always polite, and there was the great observatory built for my mother Queen Artemis, and I remember hearing that the bastion was a fortress in the Dragon Wars I heard that from-" Celestia mentally stopped herself.
"...I heard that from my teacher." Celestia completed her sentence with a tiny warm tear streaming down her ancient long face. "Celestia, you are too old a mare for crying. You told yourself that you wouldn't cry after all these thousands of years, right?"
But Princess Celestia did not stop crying. In fact, as she made her way up stairs to one of the highest spires in Canterlot Castle, the remembrance spire, she was still sobbing over the memories that were going to come for her.
Here they are.
The remembrance tower was dark, very dark. The almost total darkness in the room was due to an old Equestria tradition of keeping sacred or special objects in a dark room. It was a slender hall of a room since it was the top of a tower, and the only natural light came from a window at the end of the room. In the room itself, the dark expanse was filled with relics of Equestria's planet's past, all neatly placed on museum-like square legless display tables. Everyone of these tables were placed near walls opposite to one another so a pony could walk up to the end of the room through the room's center. The window at the end of the hall-room shone it's light on the last square table: a pedestal with the remains of clothes and armor worn by some great pony of the past.
As Princess Celestia walked down that hall of a room, feelings welled up inside of her that could only be compared to that of when a stallion sees his mare-bride coming up to him in a wedding. Only the princess' feelings were that of bad nostalgia and anguish. She knew who's clothes and armor those were.
By the time Celestia had got to the table at the end of the hall-room, she was practically bawling overtop the outfit and metal armor. In fact, the clothes were now wet with the princess of the sun's tears.
"Why did it end this way? Why did it HAVE to end this way?" The Princess mourned. "It was so, so, long ago, but the pain is yet felt, my teacher. The days we spent together were so precious." Celestia was starting to calm down, and her crying was down to a couple of happy tears due to a focus on happier memories. "We used to play in the sun together, run along on the beach, tell me stories, teach me about magic..." Celestia's list of the great things she did with the pony whose clothes lay before her went on and on.
"If only..." Celestia remembered that time travel magic was forbidden in the cases of personal needs (this even included the personal needs of a princess) by the laws of magic. And another law of magic stated that time travel magic cannot be used to go back or forward more than 100 years unless in extreme conditions.
Celestia let out a great sigh. There was nothing she could do to bring her teacher back.
"I wish...I wish I was just...with you again." Princess Celestia kneeled all four of her legs to the altar like table.
And in Celestia's heavy heart, she made a wish that she could be with her old mentor:
In another place, in another time...