((Prompt: The Thousand-Year Door.))
I choked on a cloud of dust, nearly dropping my torch as I did. That would have been bad. I was hundreds of meters deep in a twisted labyrinth of ancient stone hallways, and that torch was the only source of light between here and the surface. If that went out, I was lost down here forever.
I straightened my hat, and took a good look at what had released the dust into the dead, still air. It seemed that, quite by accident, I had leaned against a false panel in the wall, setting it loose against its neighbors. I marveled at the stonework; it was completely identical to the panels on either side of it, and I had to wonder just how many explorers had walked past it without ever knowing.
My heartbeat quickened as I pulled the stone panel aside to reveal a secret tunnel. This could very well be it. The lost piece of evidence that would be the key to what had happened to the Lost Princess. According to most theories, this temple had been the last known location of the alicorn known in legends as Twilight before she had disappeared. The temple was called the Princess's Tomb by the locals, though I suspect they named it so primarily to draw tourists.
I kept my torch wedged carefully under my wing and climbed into the hidden passageway. It was very narrow for a few paces, but widened out into another finely-carved corridor. I took out my notepad and marked the location down so that I could show the others when I returned. Glyph would no doubt be thrilled to see the stone carvings down here.
Putting my notepad and pen back, I continued on, eager to see where this new passage led. That was my big mistake. Rookies get eager. Professionals know better. Professionals know that when a pony gets eager, they miss things.
At the end of the first section of hallway, the floor took a sudden slant downwards. If I had been paying attention, I might have noticed this fact before I was falling nose-first down a not-so-smooth stone slide. Scrapes and bruises added themselves to my collection as I tumbled head over hooves for who knows how long.
When I finally skidded to a stop at the bottom, my torch was good and broken. I could feel a jagged half of it poking me in the ribs. That was just great. Just great indeed. Brilliant work.
Pushing myself up, I checked myself for serious damage other than being lost for good in a passage nopony knows about. No broken bones, anyway. But I might have had a concussion, because I swore I saw light up ahead of me. Kicking aside the torch, which was now nothing more than a burnt, broken stick, I made my way toward the light, with careful steps this time, lest I have another fall.
There wasn't supposed to be anypony down here. But that didn't stop the blue pegasus in front of me from being there. She stared right at me, from her place standing next to an elaborately-carved stone door. The light in the area came from a lightning bolt-shaped pendant that hung from her neck.
Wait a minute... blue pegasus, rainbow mane, lightning bolt. I dug through my notes. There was no way. This mare exactly matched the description of one of the Elements of Harmony, who had accompanied the Lost Princess. But that was impossible! They were from a thousand years ago!
I don't consider myself a superstitious mare. I don't generally believe in ghosts or curses. But seeing something like that before my own eyes, well, it's hard to keep from panicking just a little. My hooves edged away, back toward the darkness.
“Wait!” the pegasus said. I froze. “Don't go. It's been...” She glanced up at the stone ceiling. “...It's been a long time since I had somepony to talk to.”
I blinked. Biting my lip nervously, I took a few steps forward. “If this is you in a wig and fake wings, Check Mark, I swear I'm going to beat your horseshoes right off.”
The mysterious pony chuckled. “Heh, that would be a good one. She sounds like my kinda pony. But,” she flapped her wings, sending motes of dust rising into the air, “No fake wings, sorry. No wig, either, but don't go pulling my tail to test it.”
I nodded. “Are you...”
“Rainbow Dash,” she said, nodding proudly. “The one and only.”
“B-but that's impossible!” I stammered. “You should be dead almost a thousand years ago!”
A sad glint found Rainbow's eye. “I'm supposed to stay by this door, and wait for Twilight,” she said. “That's what she told me to do.”
My mouth worked soundlessly.
She glanced down at her pendant, which glowed softly. “At first, it was hard,” she said. “I was hungry, and tired, and it hurt. But then this thing started glowing. Afterwards, all I needed to do was remember who I'm doing this for, and I'm not tired anymore.”
I stared at the lightning-shaped jewel. The Elements of Harmony were renowned as powerful artifacts. Perhaps one could sustain a pony for a thousand years? I licked my lips. “So... the Los—er, um the Princess is behind that door?” I pointed my hoof at the large door behind her.
Rainbow Dash nodded. “She'll be back soon. That's what she said.”
I frowned. Had she missed the part about a thousand years? “What's back there?”
She didn't answer. Instead, she looked at my hat and laughed quietly. “You look almost like Daring Do,” she said. “Coat color and cutie mark are wrong though.”
I had no idea what she was talking about. I shifted my hat on my head and stepped toward the door. “Well, maybe I could go through and see if I can find the Princess, tell her you're waiting for her.”
If I had any doubt that she was solid, those doubts were dispelled as a hoof pressed against my chest. Rainbow Dash shook her head. “I'm supposed to wait for her, and nopony else is supposed to go through this door,” she said firmly.
I stumbled backwards. With a broken torch, there was no way for me to get back up to camp. The door there was the only possibility I might find another way out of here. My lip curled in frustration.
A sympathetic smile spread across the ancient guardian's face. “I'm sorry,” she said. “But maybe you can wait for Twilight with me, for a little while. She shouldn't be too much longer.”