((Edited by DoomManta, thanks again brony.))

Echoes... 

Echoes of the past...

Echoes of my hoofbeats on the melted flagstones...

Echoes of the memories of the dying...

Echoes of my friends... 

Echoes of better times... for me at least...

I wish I could be more upbeat about this, but there really is nothing to be happy about as I walk the once pristine streets of Canterlot. The formerly white stores are stained a dark crimson by the blood that was coughed up that day two years ago, the streets still stink of the decay of two million ponies as their flesh is slowly consumed by the few decomposers that can survive the green miasma that chokes what is left of this grave.

It all started with a few small developments, but it became so much more over time. Larger and larger projects, posing more and more risk to the city took over the skyline, great factories fueled the city as it grew, supplying everything from manufactured foods to industrial chemicals like the acid that has replaced my blood.

That was a surreal discovery; watching a glowing green ooze fall from a cut on my fetlock, and then eat through the stone I was standing on.

Gah, I'm getting ahead of myself... My name is Twilight Sparkle. Former student of Princess Celestia and Princess Luna, Bearer of the Element of Magic, and now, monster of the Canterlot Wastes.

Anyhow, back to the story at hoof. As Canterlot grew, soon encompassing the whole mountain it resided on, old projects were forgotten. Buried by the new, the shiny, the cutting edge, these ecological disasters seeped down into the caves below the mountain, tainting the crystals there. The chemicals formed an acidic compound, I call it 'The Glow' due to its fluorescent nature, which vaporized and built up within the tunnels, pressurizing them.

It wasn't the first strike the old projects hit Canterlot with, merely the killing blow. Before The Glow came the Nanoplauges, swarms of microscopic magical machines that were designed to help everypony...

They didn't. 

Some of the swarms simply shut down your brain, those were the ones you hoped you'd fall victim to if you saw a shimmering cloud around you...

The rest... It varied. Some ate the flesh from your bones, some ate the bones from your flesh, some paralyzed, some liquefied... the list went on. Soon enough, ponies developed the solution, an EMP.

The Electro-Magical Pulse was supposed to shut down the Nanoplauges for good, it only put them to sleep.

Then one day, they woke up, rose up from the dust around us and attacked once more. Sometime during the turmoil I walked into one... It was almost the worst pain I have ever felt... Then... the sealed tunnels below the city could no longer hold the pressurized Glow, and it escaped, hundreds of thousands of cubic meters of the glowing gas erupted into the sewers, spewing out of manhole covers, out of drains, power boxes whose conduits ran to the underground...

The Princesses were fortunately out of the city with Shining and Cadence when it happened... I'd hate for them to have to endure the pain I did. 

Ponies choked on their own blood as the Miasma destroyed their respiratory system. Others simply dissolved.

I... changed. The Glow somehow left me alive, but turned my blood into an acid so strong it can eat through glass. The Nanoplauge I had been caught in went haywire, changing me inside, I no longer need to breathe and my eyes have become green and draconic... I don't know how, but I’m certain that more than just that changed. I haven’t eaten or slept in two years... 

And to top it off... I am alone. There was no rescue sent, no attempt to save those dying.

They just magicked up a wall, tall enough to contain the city's toxic cloud as it killed. They sealed off the top with a pane of diamond that allowed light in. 

I saw the Princesses looking in one day; I tried to show them I was alive...

But they either didn’t see the flare I fired, or they ignored it. After that, nopony has walked on the diamond roof since. I want to hate them for not looking harder… for not saving me, but I know better than anypony that to come here would be suicidal.

Now, I wander, alone as I record my very thoughts onto the gems I carry. There is no rain to sooth my parched throat, no water at all, just poison. Oily sludge cascades down the gutters, the sewers having long since filled to capacity. 

I look at a skeleton as I pass, the dirty, acid bleached bones all that remain of a joyful life.

The pony is clutching a book in his hooves, it is surprisingly well preserved and bears the mark of the Canterlot Archives.

Interesting... I think, picking up the book, my magic still its gentle purple as the skeleton crumbles. 

Noticing a bookmark, I open the pages.

April Fourth, third year after the Rebellion of the Moon

The tunnel is progressing well, and the escape route for the palace staff, should they ever need to, is nearing completion. Once we finish, we will seal up both ends with a marking spell and notify Her Royal Highness Princess Celestia of its location, the far end reaching all the way out into the Whitetail Wood. To help preserve our work, and the air quality, Celestia herself is laying down the preservation spells, guaranteed to filter out even the nastiest of toxic gasses that plague tunnels such as these. Our work shall remain for years to come, I hope we never need to use it.

~Tattered Scrolls, recorder, Canterville Castle. 

It can't be... Can it? Scribbled onto a sheet of parchment is a rough map detailing the location of the tunnel, beginning directly below the castle archives. A way past the wall... If I can reach it, I can escape... 

A simple glance at the castle tells me that will be no easy feat. After the incident, vast explosions rocked the city and fires broke out everywhere, with nopony left to control the factories, the damage was… severe. The castle sat just above a manufacturing plant for the city’s fuel, the explosion had been visible from across the city, blackening the castle and weakening it. Once, shortly after Canterlot was sealed, I went to the castle to look for the library and I barely made it out of that death trap, I was almost crushed six times by collapsing walls or ceilings.

Is it worth the risk? I couldn't help but think. To leave this place? Is it worth the risk?

I thought back to before this happened, to my mentors, to my parents, to my brother... to my...

To my friends...

The rock boiled at my feet as acid green drops fell from my eyes. I fell to the ground crying, the first time I had cried in months, the first time I had felt anything in months. 

I decided there and then that this city would no longer hold me in its death, and that I would rise up and live once more.

I decided that even death was better than remaining here.

I decided that, even after two years of no contact, no way out, no hope...

I decided to place my hope of escape with a book.

I was leaving, alive or dead, I was leaving.

My home for the past few years had been a clothing store, which was now filled with the various nick-knacks I had collected in my wanderings. The shelves were full of baubles and trinkets of the city's grander days. A steam valve here, a coffee tin full of shiny bits there, a...

A photo I found of the Princesses and my friends, it was from my last birthday before the city died...

Anything and everything occupied the sturdy false-wood shelving, a collection of junk, yes, but it kept me sane. One has to have a hobby in a place like this; it is all you can do. 

I levitated the last two gifts from my friends over to me, one, brass flight goggles from Rainbow, Fluttershy, and Rarity. The other, a small shoulder bag, courtesy of Applejack and Pinkie Pie. I placed the photo in the bag, alongside a few light cells, a former Royal Guard's sword, some rope, and my memory gems. 

Trotting over to another wall of the store, I pulled down a bolt of olive drab cloth that was hanging there. I sliced out a square and tied it around my neck after donning the goggles and shoulder bag. I tied the rest around my legs to help cut down on the number of inevitable scrapes I was going to get climbing through rubble. I looked around at my collection of objects and smiled. Someday, somepony would find this place, once the air was clean again, and the city was cleansed, and they would be fascinated at all of the things that were here. 

I closed the door behind me as I left, latching the deadbolt out of habit from so long ago. I took one last look at the shop, and began my ascent.

My hoofbeats echoed on the stone of the Canterlot Market, the first major obstacle to my route up the mountain. Hidden among the Market were puddles of acid that had eroded walls and collapsed buildings across the wide street; the tall towers once used for commerce were now tall piles of rubble. Bones lay everywhere, the Glow had escaped at midday, during the middle of business hours. 

More than one skeleton was posed clutching a smaller one, or lying on top of one. Nopony was spared by the cloud, why had I survived? 

I doubt even the Princesses could give more of an answer than 'luck'.

"The fire of friendship lives in our hearts, as long as it burns, we cannot drift apart..." I sang quietly, my voice was mercifully unchanged, it was one of the few things that still felt me. The sound of my voice echoed through the mall as I clamored over the fallen buildings and through crumbling stores. 

I was the only thing making sound in the market, aside from the occasional rock falling free from its acid spattered perch.

Wait...

I whirled around to look at the towers behind me, in the direction the rock had fallen from, and then I looked up.

A pane of glass larger than me smashed to the stone as I rolled out of the way, scrambling to escape the shimmering display of falling glass that threatened to slice me in two. Sliding the goggles over my eyes with magic as I ran, I dodged pane after pane of glass falling from one of the towers. I felt a shard embed itself in my back, but the pain slowly disappeared as my acidic blood dissolved the unwanted object and my body stitched itself shut. 

As the glass stopped falling, I slowed and turned to look behind me... It was breathtaking.

The whole street glittered as if in the first snow, the luminescent green mist causing the glass to shimmer and dance as the shimmering dust in the air glistened as if it were rain. I never thought I would see anything beautiful in these ruins, for that matter, I didn’t think beauty was possible in these ruins, but this was something truly special. I removed the goggles and took one last look before I started walking again, the Market District fading into the mansions and homes of the rich and noble.

The pristine lawns and massive homes of the nobility fared even worse than the Market District; they were mostly constructed from organic materials, especially wood. Piles of rot were all that remained of many homes, piles of rot surrounded by small ponds of acidic sludge. 

A river from the mountain, poisoned by the Glow, ran across my path. At one point, there had been a wooden bridge across it, but it was long gone, consumed like everything else. I focused my magic, and with a bright flash I was across, the glowing water burbling as I continued on to my access to the castle, my brother's house.

My hooves were silent on the rotted carpets of the home, the stone having held from the onslaught of acid.

You know... I've never really taken a look around in here... I decided to explore a little before leaving, and went up the stairs instead of descending into the cellar. 

I found three rooms upstairs, two bedrooms and a washroom. Modest for the Captain of the Guard, but that was how Shining liked it, simple, spartan. I'm sure the carpets were Cadence's idea. I hoofed open the door to their bedroom first.

It was well preserved, the bed still looked intact, but I knew not to trust looks. I opted to instead look through the cabinets.

I opened the first cabinet and found various dresses, Cadence's no doubt.  There was a jewelry box at the bottom, which I set aside to look at later. The other cabinet had Shining's Dress Uniform, still in pristine condition. Taking the entire uniform was unrealistic, but I did take all of the ribbons and medallions off of it, some of them were one of a kind and Shining should have them back. 

Working through the rest of the room I found some other small things to bring, a photo album from the wedding, Shining's old teddy bear, and my grandfather's pocket watch to name a few. In the jewelry box though, I couldn’t believe what was inside.

Sitting atop the other bits of jewelry were two simple gold bands, the same two that were present in every picture of the bride and groom after the ceremony. 

In Equestria, wedding bands are irreplaceable treasures, each one is linked with the pony who gave it to their partner. They’re only ever made once, out of metal linked to the pony at birth, and formed into their final shape only days before the wedding.

Losing them would be akin to losing a small part of yourself.

I quickly closed the jewelry box and set it in my bag, the 'bag of holding' enchantment I had placed on it years ago holding strong. I stepped from the room one last time, and crossed the hall.

I pushed the door open to the former guest room, now housing all the necessities for a foal. I had forgotten that Cadence had been nearing the end of her first pregnancy, and for a moment, I wondered what being an aunt would be like. I looked around for anything that I should take, but found nothing.

I closed the door and trotted down the stairs, heading to the cellar.

I emerged from the hidden passageway into the Gatehouse, it was filled with armor-clad skeletons. One was still locked at attention, probably a victim of a Nanoplague swarm if the silver dust around his hooves was any indication. I stepped past him and out into the castle courtyard.

I was instantly reminded of why I hadn't visited the castle in over a year and a half, the windows were gone, shattered from the force of the factory explosion. The once great doors of the castle were now but iron hinges holding air as I passed them, the wood they had held had long burnt away. Piles of rubble were all that remained of entire sections of the castle. I trekked through the castle, heading for Celestia's tower. She usually kept a key to the archives there, to allow easy access, I hoped it was still there and intact. 

The windows let in plenty of light from the sun as I walked through the Hall of the Elements, the vault door at the far end was cracked and crumbling. I trotted up to it and gave it a nudge with my magic, and jumped back as the metal turned to dust, the impenetrable star-steel doors had been reduced to nothing by the Glow. The chest of the Elements of Harmony was still there though, strangely enough. I quickly opened the chest and retrieved the necklaces and tiara, adding them to my saddlebags. As I levitated them, I felt a twinge of familiar magic; it felt peaceful, like home, like the princesses.

I left the hall and proceeded up the adjacent tower to Celestia's chambers, the doors that had stood for centuries crumbling at the slightest touch of my magic. Two lone skeletons sat at the top of the stairs, hugging each other in front of the doors they had guarded with their last breaths.

I pushed open the large door, oddly enough, they were still intact, even though the vault for the Elements had disintegrated. Celestia's chambers were just like I remembered them, right down to Philomena’s cage. I trotted over and looked into the cage and saw a pile of ash with a golden feather sticking out of it. I scooped the ash and feather into a teapot that was lying nearby and placed them into my bag. 

After a few minutes of searching, I found the key to the archives and began my descent into the depth of the castle.

Even in the windless lower levels of the castle, the Glow was present, providing me with much appreciated light. Light cells were good, but they only lasted twenty minutes minutes each, and I didn't want to waste the precious few I had.

Soon enough, I reached the gate to the archive levels. I pushed the key into the lock, twisted, and with a click and a snap, the door was unlocked. The key broke off in the keyhole, but it’s not like the gate was ever going to be used again, so it didn’t matter. 

The gate screeched on rusty hinges as I opened it, my entrance slow, reverent of the knowledge stored around me. Withdrawing the map, I went straight to where the tunnel was supposed to be. A tapestry hung there, depicting an ancient battle. I carefully levitated it down, revealing a spell inscription on the wall. 

Built by the families of those who needed a way out and never had one, so that others will not have to share the same fate.

I channeled my magic into the diagram, gasping as the bricks folded back into themselves to reveal the tunnel. I removed a light cell from my bag and activated the small orb, the light flickering into existence as I started down the tunnel.

Twenty minutes earlier...

Celestia sat bolt upright, her wings flaring out as her face took on a look of utter surprise and confusion, startling the members of the guard around her.

"Your Majesty, what's wrong?" In all his years in the Guard, Shining Armor had never seen the princess startled, and rarely saw her surprised.

"Th... the warning spell... on the chest that held the Elements..." Celestia stammered.

"What about it?" Luna asked, concerned.

"Somepony just opened the chest!" A murmur went up through the room. "Somepony is alive in Canterlot!"

"Sister, that is impossible." Luna said, looking out the window of the recently restored palace in the Everfree. 

"You're right... It has to be a coincidence... the... the castle probably collapsed." Celestia said relaxing.

Not five minutes passed before Celestia shot up again. "The spells protecting the keys in my chambers just went off as well." Celestia explained with a sigh. "The tower must have held on longer than the rest of the castle."

Fifteen minutes later Celestia jumped to her hooves and started for the door. "Shining Armor, get a chariot, pegasi to pull it, and have it retrieve the Element Bearers and your parents, and bring them to the palace. Also get a hazmat team with a quarantine chariot to Shimmering Falls in the Whitetail Wood at once!" 

"Your Majesty?" Shining asked, confused.

"There was an escape tunnel built into the archives when Canterlot Castle was built. I placed a spell on it to alert me if it was ever opened. Only a unicorn can open that passage, the spell would not trigger otherwise, and it just went off." Celestia said. "That combined with the spell on my keys... only one pony that was in Canterlot that day knew that I kept a key to the archives in my room."

"Who, Sister?" Luna asked. 

"Twilight Sparkle."

The response was immediate, Shining Armor spurred the guards in the throne room into action, the large doors slamming open as he galloped out of the throne room, shouting orders.

I can hear a waterfall... I thought as I trotted along the passageway, my horn being my only source of light by this point.

A white brick wall came into view, an identical spell diagram to the one in the archives sat, waiting to be unlocked. A quick pulse of magic was all it took to open the passageway to reveal a torrent of crystal clear water. I had finally made it.

I cast a waterproofing spell on my bag, put my goggles back on, and took my first breath of clean air in years, before stepping out into the flow. I had forgotten what water felt like, forgotten what cold felt like, so many things came rushing back to me as I was swept off my hooves and out to a sandbank.

I pulled myself to my hooves, removed the shoulder bag, and cleared the lenses of my goggles. I froze as I heard breathing near me, followed by the sound of somepony putting a hoof down.

"Twilight? I-is it really you?" That was a voice I would recognize anywhere, even after being alone for so long. It was the voice of my brother. I opened my eyes and saw his face behind a protective shield; finally, another pony.

I fought to hold back acidic tears. "Yeah, BBBFF." I said. "It's me." Behind Shining Armor, I saw four guards in protective gear trotting out of a quarantine Chariot.

"Let's get you home." He said, his voice betraying the fact that he was crying.