In retrospect, this is all that damned book’s fault.

How many times must we go over this? My story isn't going to change. Yes, I know that a pony with my history is certain to raise suspicions when something like this occurs, but I tell you once again; I am innocent of these crimes you have charged me with! My hooves are clean! What occurred in that library was all Princess Twilight's doing, you have to believe me!

Fine. If we must go over it again, then we must.

As I've already told you, I was with my mentor and teacher earlier today in Library of Canterlot Castle. Twilight had procured for me a special pass to read from the Forbidden Section, a selection of tomes that holds magics too dark and powerful for all but the most magically inclined of unicorns. When I pressed Twilight for exactly why she had chosen this as her next 'friendship lesson,' her response only caused me more confusion.

“Because you might be the first one who can actually help me do it.”

The intense look in my teacher’s eyes halted any further questioning on my part for the time being.

We pored over the arcane texts in the Forbidden Section for what felt like hours. I read about spells and possibilities that I’d only dreamed of. Did you know there's a hex in there to return youth to the elderly? Another book is just one long math-magical equation that allows one to create life from the lifeless. I recall one book in particular that held sketches that seemed to depict beings whose images made my head hurt if I tried to comprehend them for too long...

Twilight's frustrated groan made me look up sharply from my current reading. The alicorn princess was making her way towards the huge main shelf, tossing books every which way, barely looking at the covers. She was visibly frustrated, more so than I'd ever seen her before. She was doggedly in pursuit of some goal that escaped me for the time being.

I'd closed the book of sketches and reached for the next one in my pile. Even now, I recall the title with crystal clarity; De Vermis Mysteriis.

I read the title aloud and Twilight was by my side in an instant, babbling excitedly about what I'd found. It became rather obvious that the old book was the one she had been searching for. Her magic snatched it from my grasp and she began talking rapidly about the history of the book. About somepony named Ludwing Prance and his forays into the darker side of magic.

The way she told it, she'd been a filly the first time she'd snuck into the Forbidden Section. She'd found De Vermis Mysteriis and had burned an entire night lost in its pages. It was within that she had discovered an idea that had set a blazing inferno in her brain, one that had not been tempered in all the passing years; the Thirteenth Hour.

I remember the almost manic glint in her eyes when she passed the book back to me, now opened on the source of her obsessions. The Thirteenth Hour, as Prance wrote, was a concept he had stumbled upon while researching methods to get more time to study during the day. His writings referred to an hour hidden between the stroke of midnight and one, a secret sort-of pocket dimension that only a certain few were able to perceive. One's physical being was left behind, but one's mind became privy to a whole new layer of existence. In the realm of the Thirteenth Hour, time itself ceased to be. Using his newfound access to this hidden world, Prance was able to advance his mastery of the magical arts by leaps and bounds.

I remember the bitter smile on Twilight's face as she voiced her conclusion that Prance could possibly have exceeded Starswirl himself had a mob of villagers, convinced Prance was a necromancer, not burst into his home, dragged him out, and burned him at the stake.

Twilight's intensity began to frighten me. I think she could sense it and she tried to calm me down. She told me that she had known how to access the Hour for years. It was only fear of the unknown that had held her back.

Suddenly Twilight's reasoning for bringing me along became clear; she wanted me to cast a spell on her that would allow her to speak to me while her essence accessed the Thirteenth Hour. That way, I could record her findings and, if necessary, help her if she was unable to pull herself back.

I wanted to refuse her, but I found my tongue would not voice my fears. I owed everything to Twilight. Who was I to deny her request? Who was I, when this was something that had consumed her for years?

I agreed. Celestia forgive me, I agreed.

She settled herself into one of the plain wooden chairs and lit several candles so that I would be able to see what I was writing. The sun had long since sunk and the Forbidden Section was now as dark, cold, and forboding as any dungeon must be. The candles created dancing shadows on the wall, momentary faces in the darkness that seemed to leer at us and urged us on.

At Twilight's guiding, I carefully cast the consciousness spell on her. She shivered as the magic settled over her like a shroud and offered me a reassuring smile. I did my best to return it, but I imagine it must have looked more like a grimace. I watched as she examined the pages of the book and lit her own horn. I watched as her familiar purple magic flowed down her horn and coated her entire body. The violet aura began to dim and I saw a faraway look in her eyes. They glazed over, like she was falling into a deep sleep. Still, they remained wide open.

How I wish now that they had simply closed!

She began talking then. What? Did I take notes? Of course I did. No, I don't have them. Where would I be keeping them? You found me in the Forbidden Section and dragged me straight here, didn't you? Did I have time to stash them somewhere while I lay on the floor, sobbing and screaming at what I had just witnessed? Do you think I have the book as well? Go. Go back to the library and check the shelf. I'll bet you'll find it still there, untouched and smoothly clean, not touched by either dust or by soot.

...Yes. Yes I remember what she said.

Do you really want to know?

Maybe if I tell you, you'll understand. You'll finally actually listen to me and release me so that I can stop that wretched, damned thing from hurting anypony else ever again!

You want to know? Fine. I will satisfy your curiosity.

She smiled at first. I'll never forget that content smile as long as I live. "Oh Starlight." She'd whispered. Her voice was tinged with something I could only call rapturous joy. "It's everything I ever dreamed."

She described with increasing excitement how the world around her looked just like our own but frozen in time. She narrated to me her long trek through the castle while I did my best to keep up with the notes. She described a staleness in the air, like a museum that has not seen a vistor in quite some time. She traversed the castle and then the courtyard, noticing minute differences between our world and the world of the Thirteenth Hour.

She wanted to see more, she told me. She flapped her wings and took flight and I saw her physical wings twitch ever so slightly and I felt the smallest twinge of indefinable fear. I continued to write as she described the barren plains surrounding the castle.

Her voice took on a darker tone, then.

How I wish I had pulled her out at that moment!

What's that? You found one of my notes? Of course you did. You were supposed to. Where was it? On the floor by the ashes? Tell me something, sir.

Was it there before?

You want me to read it? Very well.

Ahem.

"Something's not right here, Starlight. There's some strange feeling. I can't place it... but it feels like it's pulling me. Guiding me. Like a whisper in my ear. It's calling me... North. Yes, north. Towards the mountains beyond the Crystal Empire. There's something there. I need to find out what it is."

She was quiet for a while after that. No, I'm not sure how long. It may have been minutes. It felt like hours. Eventually she spoke again, the fear a bit more prevalent in her voice.

"Starlight, I just flew over the Crystal Empire. It... it's not there. But it is. I'm not sure how to describe it. Everything looks like it's in the proper place, but when I get closer it just fades into colorful mists. There's more; the ground is slightly inclined by the Empire's borders, like it's rising. I need... I need to look closer."

She was quiet again, but only for a few seconds this time. Her glazed eyes widened and she uttered an involuntary shriek at the visions she saw now.

"I don't believe it! Starlight... it's a mountain range! But there shouldn't be any mountains here! They're... they're huge! The biggest mountains I've ever seen! I can't even see the tops! They just keep going and going, higher than the clouds! Wait... there's a pass ahead. Starlight... whatever's calling me is past these mountains! I have to go further."

I begged her to come back, to let me bring her back! She didn't even acknowledge me. Her wings were fully flapping now, purple feathers flying every which way and falling like downy snow. The flames danced atop the candles as though growing more and more excited as Twilight grew closer and closer to whatever dark discovery lay ahead of her.

"I'm past the mountains now. Starlight... I can't even describe it. It's like a valley... no! A plateau! And it goes on as far as the eye can see. The air smells different here. Not stale like before. It smells like home. Like...like it's... it's..."

She screamed then. Oh, how she screamed! I had to put my hooves over my ears to block the heinous noise and still I could hear her piercing wails! Her glazed eyes were now rolled into the back of her head, her wings branching out to the point of breaking. Her legs kicked as she tried to scrabble away from whatever was threatening her.

Or like they were trying to fight something off!

What? Finish the note? Fine, damn you!

"He's here, Starlight! He's here with them! They've been here for eons, plotting and planning and scheming! Do you understand?! They've had nothing but time because time does not exist here! The Colour out of Space! The Goat with a Thousand Young! Ph'nglui mglw'nafh Cthugha Fomalhaut n'gha-ghaa naf'lthagn!"

She spoke more in that hideous, burbling language but I couldn't follow. Finally she stopped and she began to sob.

"I was so wrong, Starlight! All these years and I was so wrong! I'm so sorry. I'm sorry I won't see you again. They're all around me now, these hellish legions! And... something else. No... you stay away from me! Get away! GET AWAY! GET AWAY!"

She spasmed for a moment, like an electrical current was going through her, and then she was still. She slumped over in the chair. Her falling wings knocked against one of the candles and it fell to the floor. The old chair she sat in went up quickly and my mentor and friend was soon lost in flames that hungrily consumed flesh and wood alike. I wish I could say I tried to save her, but I was already where you found me; curled on the floor, nearly out of my mind.

I did not kill Twilight Sparkle, but I may as well have. I'm sorry. I'm so sorry.

...

They're gone now. The guards, I mean. I know you're still there, though. I can feel you watching me in the darkness. You know I left something out, don't you? I had to. If I told them, they'd call me mad and lock me away before I can finish what must be done.

I have to get back to the library.

I have to find that cursed book and find a way to finish what the flames could not.

Why?

Don't you understand? Those mountains Twilight saw and the hideous things that lurk behind them... they are moving. Slowly, so very slowly, but they are moving still! The incline at the boundary of the Crystal Empire is the giveaway. And in time, though it may be countless millennia from now, they will pass the threshold of the Thirteenth Hour and find their way into our world. And on that terrible day, when at last the stars are right, those unknowable things will come and all will be lost. Doom will come to Equestria!

What's that? How do I know this? How do I know that things on that side can cross over into our own?

...Do you really think a single candle's flames could burn strong enough to reduce a chair to ashes, let alone an alicorn?

When Twilight collapsed, I reached out a hoof for her. I called her name, over and over again. Twilight! I cried. Twilight! Twilight!

Her head lolled horribly then and her eyes found mine. But they were no longer her eyes. They blazed with hate and wicked intelligence, with the malevolent wisdom of the ages! The mouth that was no longer my friend's fell open and hung limply before the jaw was again retracted. I could see the tongue swirling inside the mouth. It twirled in rapid circles like it was trying to remember it's purpose!

It... spoke to me, that thing in Twilight's body, a single sentence in a cracked, ageless voice. The thing's breath was rank and cold, like the air in a long sealed mausoleum. It smiled then and I saw the legs that had last been used fruitlessly to ward off evil from another world beginning to work back and forth like the mouth of the thing and I acted without thinking. My magic grabbed every candle in that room and increased their blaze a hundred fold. I focused the inferno on the thing in the chair and it screamed as it burned. It screamed and flailed and glared at me with murderous, wanton hate!

It glared at me until the eyes were but ashes and soot.

They can never know that, though. They would never believe me. They could never handle the words of the thing as it rapidly relearned how to use a mortal mouth. They could never imagine the idea of one who had escaped into his greatest discovery when his mortal form was taken and burned generations ago finding a window back into the world that he so hated and despised. They will never hear the words I heard the thing speak in the voice not of the Princess of Friendship, but in the mold-encrusted tones of the sorcerer once known as Ludwing Prance!

The words that will haunt my sleep until my dying day.

"You fool, Twilight Sparkle is dead!"