The Doctor hadn't stopped babbling for about twenty minutes. River tried her best to keep up with him, but when he was like this there was no hope.
As soon as the Princess told them she would arrange for transport to her castle to explain, the Doctor had grabbed River.
"You remember House? The consciousness that had inhabited that junk planet?"
"No, I –"
"Well, I think that's what this is!" He jumped up and down. "I mean, it's a lot bigger. And a more pervasive. And actually attached to a being." He stopped and looked thoughtful. "Okay, so it's nothing like House. BUT STILL!"
Ditzy watched the Doctor closely, not even trying to hide her confusion. As hard a time as River was having, she was sure that the pony didn't understand half as much. River caught her eye and rolled her eyes jokingly. Ditzy smiled back. If the Doctor liked Ditzy, she might as well give her a try.
Before River could strike up a conversation with the pegasus, a chariot fell from the sky. Well, not fell; it was being pulled by two pegasi with straight faces. River was confused by this; the ponies were acting like… well like the horses of Earth, content with being the beasts of burden. How far down the social ladder do you have to go to get that job? River wondered.
The Doctor had seemed to notice the same thing. "Maybe they're prisoners, being punished," he muttered to her, low enough so Ditzy couldn't hear.
"I suppose we could ask," River whispered back.
He beamed at her. "Oh, River Song. The answer is always easy, isn't it?" He cantered over to the carriage.
"Hello gentlemen!"
The two pegasi stared at him hostilely. Of course, that didn't deter the Doctor.
"I was just wondering if you could tell me how you came across this job. I'm looking for work myself, and I couldn't help but notice that this seems like a viable position in society."
They continued to glare at him, and River couldn't help but feel that he had offended them. "Retreat, retreat!" she whispered, half-jokingly. The Doctor clambered into the chariot, followed by River and Ditzy.
Once they were in the air, Ditzy hissed at the Doctor, "Why did you ask them about pulling the carriage?"
River and the Doctor were both taken aback by her tone. She was blunt, bordering on harsh. River spoke up first. "We were just curious, seeing as how most of you have respectable –"
"They can't talk. That's why they're reduced to that. They aren't normal ponies, can't talk or think like the rest of us. They aren't… they aren't right." Ditzy looked away from the couple. She seemed shaken, maybe even offended. River glanced at the Doctor, who was watching Ditzy closely, as though he was solving a puzzle.
The rest of the ride was in silence. Ditzy watched the scenery below, the Doctor watched Ditzy, and River watched the Doctor. What an odd team we are, she mused. But more important in her head was getting out of here. This world was different; too different for them to really be a part of. She knew the Doctor wouldn't accept that. He had latched on to these ponies the way he latched on to Earth. He wanted to solve all of their problems for them, refusing to let nature take its course. That stubborn, beautiful man.
When the chariot set down, the princess was outside waiting for them. The three companions bowed before her, and she bent her head in return.
"Doctor, River, Ditzy." River still wasn't used to hearing that voice inside her head, let alone outside of it. She suppressed a shiver as Celestia welcomed them to Canterlot.
"Princess," the Doctor began immediately, but she held up a hoof to silence him.
"I will talk to you three inside. It's not safe here." River watched Celestia carefully, but it hadn't taken any visible effort on her part to convey that psychic message. Her hair flowed elegantly behind her, never stopping for a moment. She turned gracefully, nodding slightly to her guards. They pressed in on both sides of the travelers, and they were ushered into a tower room, one with magnificent stained glass and jewels embedded in the walls. With another nod, the guards were dismissed. The princess's horn glowed brightly as the doors shut. She stared at the door as though watching for some sign.
After a few silent moments she sighed, her demeanor changing visibly. She shut her eyes for a moment and River realized simultaneously that the princess was very young and very old. She remembered the Doctor saying that it was over a thousand years into her reign, and yet she appeared so young and naïve. It reminded River of someone else.
"Doctor, by now I am sure that you have figured out that Equestria is not as perfect as it seems." The princess opened her eyes and stared at him. "I've had reports of monsters in all regions of my land being thwarted by two particular ponies." The Doctor smiled a bit, throwing a wink at Ditzy. "In addition to that, rumors have been flying around of a blue box that seems to appear anywhere these two peculiar ponies show up." Celestia smiled down at them. "Let me start off by thanking you for that. You've certainly made my job easier."
"You are very welcome, ma'am," the Doctor said with a bow. Ditzy took the hint and awkwardly curtsied a bit.
"But there's something you do not know Doctor." All three of the companions straightened up, knowing that this was what Celestia had wanted to tell them. The princess closed her eyes wearily again.
"One thousand years ago, Equestria was ruled over jointly by my sister, Luna, and myself. I watched over the day; Luna, the night. For five hundred and fifty-six years we guarded Equestria like this, keeping it safe from harm.
"Or so we thought…" she murmured. She opened her eyes, gaze drifting to one of the windows. Celestia paused for a moment, as though composing herself.
"One day, after I had lowered the sun and returned to the palace, Luna seemed troubled. She didn't want to raise the moon, let alone leave the palace. 'It's going to get me,' she said. If only I had listened." The princess bowed her head again, but continued with her story. "The next morning, I woke to find that Luna hadn't lowered the moon. I immediately went to where she usually stayed at night, a tower in the Everfree forest. As I approached, something caught a hold of me, pulling at my mane and tail, trying to stop me from entering. I fought it, running full speed to the door. I kicked it down and saw…" Celestia took a shaky breath. "I saw some… thing surrounding my sister, absorbing into her. I tried to run to her but I couldn't… I couldn't get close."
Every word out of Celestia's mouth seemed to hurt her more, to bring her closer to tears. River felt the urge to hold her and tell her it was alright, that she understood. And she did understand. She knew what it was like to see something out of your control hurt the most important person in your life, to be completely powerless as they suffered. She leaned subconsciously towards the Doctor, who rubbed his chin on her neck comfortingly. He knew what she was thinking of, of course. He always knew.
Celestia collected herself again. "The thing possessed her, turned her against me. She became what went down in legend as 'Nightmare Moon.' I refused to let anyone stain her name with something that was not her.
"As the story goes, I banished her to the moon. But it wasn't that simple. By myself, I was too weak to fight Nightmare Moon. I needed aid. First I turned to the Elements of Harmony, a weapon Luna and I had used against another enemy long before." Her eyes focused on another window, and River realized that each of the stained glasses told a different story. What I wouldn't give to dig up something like that! She suddenly imagined the Doctor calling her an archaeologist, and couldn't help but smile at herself. She turned her attention to the princess.
"But they weren't enough; by myself I couldn't use them all. I went to the tower that Luna had been taken in and looked for clues. But as it turns out, the clues went looking for me. While I was there, I felt something approach. I was terrified, afraid it was the same dark force coming to possess me. But it was different. It was light and warm, like the feeling of the first rays of the sun after a cold winter night. I knew it was good… or at least I hoped so.
"It spoke to me, told me of its world. The darkness was its enemy as well. It had chased the darkness to Equestria, but before it could stop it, the dark had possessed Luna. It asked me for help, and I realized what had to be done." Celestia's eyes were open now, blazing straight ahead. "I fought fire with fire. I allowed the light to join with me so I could get my sister back."
"How?" asked the Doctor, his eyes wide. The princess smiled down at him kindly.
"I don't remember much about the process. It was dark out, as Nightmare Moon would not lower the moon, but inside it was as bright as a summer day. I remember feeling warmth, never overwhelmingly hot, just a nice warmth. I suddenly felt connected with everything in Equestria, as though every animal, plant, and pony was in my mind, helping me find the strength to carry on.
But even together, we were not strong enough to separate the two. Destroying one would destroy the other. So, using the Elements of Harmony and my own powers, I banished Nightmare Moon for what I hoped was eternity. I put her in a deep sleep so that she couldn't fight the spell."
"But it didn't work, did it? She came back last year." Ditzy surprised everyone by speaking up, herself included. She bowed her head shyly after she spoke, as though trying to take back her words. Celestia looked down at her with pain in her eyes.
"Yes. About a year ago I felt something… wrong. I was still deeply connected to all of Equestria, and I knew that this had to be related to Nightmare Moon. Though I was stronger, I did not want to face her directly. I had been training a student for some time; a student who I knew could use the Elements of Harmony in a way that I had never imagined. If anyone could separate the darkness from Luna, it was Twilight Sparkle."
River barely concealed a gasp. Twilight Sparkle? The unicorn that she had stayed with in Ponyville? She hadn't seemed particularly powerful, just a bit too curious for her own good.
"I sent out all of my consciousness to aid her and her friends. That's why I was missing, Ditzy. I knew Nightmare Moon could defeat my body, so I sent my soul. Together with her friends, Twilight separated the darkness from my sister… and then I destroyed the darkness."
The ponies stood in silence after Celestia's tale. River looked back on it, wondering why this had caused the princess to call them together. The Doctor seemed to be thinking the same thing, but he held his tongue. It was Ditzy who spoke up again.
"What does that have to do with us, Princess? The darkness was defeated."
Celestia smiled at them all. "Yes, it was. But there is one issue. One that I'm sure you've noticed, Doctor." River looked at the Doctor, who stood there, concern in his eyes.
"You're still connected to the other consciousness."
Celestia nodded sadly. "Do you see why I called you here, Doctor? You're the only one who can help us. The only one who knows about other worlds, the only one who can separate dimensions."
She knelt down before him, eyes full of pain. Her voice and very manner seemed to have changed. "I just want to go home, Time Lord."