Year of Celestia’s reign: 799 ABNM. (After Banishing Nightmare Moon.)
Canterlot, along with the whole nation was getting ready for the upcoming Summer Sun Celebration. Where the whole country will party all night to pass the time until the dawn of a new year of Celestia’s reign. A day that marks the defeat of Nightmare Moon by the courage and sacrifice of the Sun monarch.
Each year, upon royal request, Celestia would spend twenty-four hours alone before the event. Every year alone in her room, no doubt to mourn over her sister. Those who worked in Canterlot’s castle would say that each year, they would hear something rare; Celestia’s cries that hauntingly echo throughout the halls.
It was on that day on the eve of her 800th reign alone that Celestia received a very unusual visit. While grieving in her large room, Celestia heard a sound. In her lifetime, she heard it a few times, but the sound of a mechanical weaseling and groaning was something she recognized immediately.
As the sound grew louder, she looked up to the source of the sound, and sure enough, it was coming right in front of her. The darkened room was lighting up with the materializing of that blue box that says “Police Public Call Box.”
Once the box was made real, the sound ceased. Moments later, there was a sound of doors opening from the other side. Then she heard a voice that said: “Are you certain this is Equestria and not on some other planet?”
At first, she couldn’t recognize the voice right away; it was female and sounded full grown. But why did she sound so, familiar?
“I’m absolutely certain.” The replay, Celestia noted, came from a stallion’s voice. But unlike the other, she realized whose voice it belonged to.
“So if this is Equestria, where exactly are we?”
“Let me check… Canterlot. The TARDIS says we’re in Canterlot.”
“Canter- where?”
“Oh! We are in Equestria’s capital.”
“So did they rename the capital in the future?”
“Uh, no, this is in a different part of Equestria. And, why is it dark? It’s supposed to be two o’clock in the afternoon.”
“Maybe Celie has forgotten to raise the sun again.” With that joke, Celestia rose up, that voice, now she knows why it sounded familiar. If her long memory serves her right, that voice could only belong to one pony, somepony whom she hasn’t seen in centuries.
“Luna?” Celestia called out.
She heard hoofsteps that came from inside the blue box, and then she heard them on the marble floor. “Celie? Where are you?” Then the mare peaked to the left side of the box. At first, Celestia froze with wide eyes, as if a phantom had appeared right before her. But she saw her. The blue alicorn with a dark crown and chest piece with silver shoes. It was the one who she was crying over the past several centuries.
“Celestia, what’s wrong?” Her sister asked, “And why are you crying?”
“LUNA!!!” Celestia pounced on her little sister, hugging her tightly. “Oh Luna! I’m sorry! I’m so sorry!”
“Cel, let go of me!” Luna struggled for air in her sister’s death grip of a hug. Celestia did loosen her grip but still embraced her and kept on crying. “What happened?” Luna asked her sister and looked around the room. “Has something tragic happen? Celie, please tell me, why are you crying?”
“I missed you,” Celestia said through her sobs. “I missed you so much.”
“Was I away for too long? I’ve only been gone for only a few days. And, have you been growing lately?”
“It’s been too long.”
“Really?”
“Uh, Luna.” Celestia looked up to the voice of the Doctor. She was just like the last time she saw him. Dark brown mane with a tan coat and an hourglass as his cutie mark. Once Celestia saw him, the Doctor seemed to get very uncomfortable: “Well… This is certainly awkward.”
Celestia let go of Luna and sat upright, “Luna, when was the last time you saw me?”
“Last time? I asked you if I could go with the Doctor and you said yes, why?”
Celestia stared at her younger sister, taking it all in. Upon closer examination, her sister seemed a good deal younger before “it” happened. She was shorter and her mane hadn’t gotten to that flowing starry night stage yet.
“It’s just...” -Celestia trailed off, trying to think carefully what to say next- “It’s just that it has been a while since the last time I saw you.”
“Have I been traveling with the Doctor for too long?”
“Well… Not exactly, it’s just you’ve been away, but for a different reason.”
“Hmm… I should probably come back a whole lot sooner, Doctor, maybe you could-”
“Wait!” Celestia reached a hoof to her sister. “Please stay, at least, with me here for today.”
Luna gave her older sister a puzzling look. “Sister, are you alright? Is there something you’re not telling me?”
Celestia looked over to the Doctor, in his eyes, she saw him pleading not to tell her.
“It’s complicated.” She said at last. “Extremely complicated.”
Luna raised an eyebrow. “Sister, you’ve been crying in here in your room (or at least, I think it’s your room) in some new capital city with a different name with the curtains drawn. And not only that, you’re the one who’s asking for my forgiveness? For what? Did you make me run away or something? In fact, how long have I been gone?”
Celestia shook her head. “Luna, I can’t tell you-”
“Why not!” Luna interjected. Suddenly, they heard a knock.
“Princess Celestia? Is everything alright in there?” a voice asked.
Luna was about to answer, but she found that she couldn’t open her own muzzle, she found it was closed shut by Celestia’s aura.
“Everything is fine!” Celestia replied.
“Are you sure? Is somepony in there with you?”
“No. In fact, I don’t want anypony in the hallway, not even a single guard.”
“But princess-”
“That’s an order!” Celestia snapped.
“….Yes, your majesty.” And with that, they heard fainting hoofsteps. In fact, Celestia didn’t let go of her magic until they couldn’t hear them.
“Celestia, I must protest.” Luna said, looking at her sister annoyed, “What is going on? Are you trying to hide me for some reason?”
“I have to,” Celestia said. “Nopony must ever know that you’ve returned.”
“Returned? Celie, tell me, what are you even talking about? How long have I been away?”
Celestia closed her eyes for a moment before responding. “Luna, the last time I’ve ever seen you, was about eight hundred years ago.”
Luna sat there, registering what she just heard: “What?” was all Luna was capable of asking.