Darkness choked me.

I walked forward and tenderly scraped my hooves across the ground so I wouldn't trip. My wings were stretched out to my sides, and I felt the rocky walls brush against my feathers. I tried lighting my horn, but the magic was snuffed out like a match in a breeze.

Breathing. Something cold touched my neck, and I jolted forward. There was no light, but I felt the shadows churn around me. A wing. An eye. Teeth and claws. I broke into a gallop, but my legs were sluggish.

I pumped my legs with all my might, but I was swimming through mud. My hooves were numb from the chill that gripped my heart. There was something behind me. I needed to get away. Shadows clung to me like chains.

"Help!" I screamed.

My voice warbled with a distorted echo like I was underwater. It resonated through the tunnel as I struggled forward. Then left. Right. I tripped, falling down a shaft and bashing my chin, but I scrambled to my hooves and scurried through the maze like a rat.

The tunnel narrowed, and the rock squeezed against my barrel like a hundred tiny teeth. I gasped, breaths coming in short bursts as the walls and ceiling pressed down on me. Trapped. It was still coming. I needed to get away. Think. No, not think. Run. I had to run.

I pushed through the narrow opening with all my might, screaming in desperation, and I popped loose. There was a tearing sound and something wet flopped at my hooves, but I ignored it and galloped forward. Mushrooms the size of trees towered above me, and motes of light flickered between them like fireflies. I stopped, transfixed by the sight.

What was I doing? There was something important happening. I needed to be somewhere… to be doing something. What was it?

Where was I?

… Who was I?

I stumbled through the mushroom forest's underbrush. A spore cloud drifted past me, and the putrid scent of rotting eggs, cabbage, and fruit caressed my nose. Something pony-shaped tripped me, and I caught myself on the trunk of a fungal tree. I looked back, and wormy eyes stared at me, pleading.

"Sorry, sir… or ma'am?" I rasped. "I'm sorry, but I'm very busy."

I continued my stroll through the woods, marveling at the strange life around me. If only I had a sketchbook to record some of these new species. My mind whirled at the possibilities. A whole volume could be published on my findings alone in this grove. I couldn't wait to show Princess…

Princess… something. I blinked. It was hard to think. What was I doing? Fog clouded my mind, and thoughts drifted away like vapor.

Snap! A twig broke beyond the treeline, and I whirled around. Shapes, dark and shadowy shapes, flowed through the mushrooms toward me, and I remembered. Something was chasing me, and I was running. I spread my wings to take flight and jumped…

And I crashed into the ground. The floor was spongy and smelled of musty mothballs. I looked behind me, and my back was drenched in blood. Two bony stubs twitched where my wings once were, and I gasped in silent horror. Even as I watched, green and yellow fungus sprouted from the wounds and crawled up my back. Mushrooms, dressed in fine gossamer-like filaments, split through the skin and fur where my wings used to be. I flapped, and they moved like wings, but the fungal infection spread with every motion.

I broke into another gallop. Puffs of spores followed my wake, and strange shapes emerged from the forest floor. They were shaped like ponies, but their bodies were covered in pulsating growths and mushrooms that twitched like antennae. The fungal zomponies shambled after me, gasping raspy groans, and my scream came out as a gargled wail.

Mushrooms zipped past me as I scrambled through the forest. Everywhere I turned, more zomponies waited for me. They reached out, begging and pleading or with hateful hunger. I couldn't tell which, but I knew I couldn't let them touch me, or it would all be over.

A chasm yawned before me, and I skidded to a stop. Fungal death was behind me; hungry darkness was before me. The jump wasn't too far—a mere dozen hooves. I could make it.

I sprung forward like a cat, but my hoof slipped at the last moment, and the leap came short. The forest disappeared as I fell into the darkness. Down, down, I fell. A buzz droned in my ears. It was like a horde of flies churned outside of my vision. The blackness swallowed me, and I landed in a heap.

The ground was soft and yielded to my weight. I stood, though getting my hooves underneath me was a challenge. They sunk into the ground with a wet squelch, and a shiver went up my spine as I lit my horn. I saw an endless expanse, no walls or ceiling – just an empty void. Bile rose to my throat as I looked down. The ground was… moving. It undulated and rippled. A sea of maggots writhed beneath my hooves, and it was rising.

I screamed, and my horn burst into lavender flames. The fire spread before me like a maelstrom and burned away the churning tide. My magic cleansed away the rot and decay and lit up the darkness, but something else reached out in turn.

An oily tentacle wrapped around my hoof, and I lashed out with a bolt of lightning. It flexed and crushed my leg with a splintering snap, and the agony snuffed out my magic. Another tentacle curled around my horn, threatening to snap it off, and I sobbed as more of the slimy appendages coiled around me like snakes. They dragged me to the ground, immobilizing me, and I sank further into something that felt like tar.

My hooves disappeared, then my barrel, and I strained my neck to keep my head above whatever was swallowing me. Cold and oily tendrils slithered along my chin and ear as I sobbed.

Princess Celestia… Spike, girls… I'm so sorry.

Greasy tar pooled into my ears and over my eyes. I clenched them shut and coughed as it pooled in my mouth. Then, as I sucked in a last gulp of air through my nostrils, something clicked.

"LUNA! HELP!" I screamed.

A deep pool of magic exploded within me. It was icy, like a mountain spring, but I did not feel cold. The magic washed over me like an autumn breeze or a bucket of water after a hot day. Tar evaporated from my lungs, and the tentacles turned to ash around me as the dream–the nightmare–fell apart.

I sat alone in a cavern. A small fire blazed in front of me that kept away the darkness. I still felt something lurking beyond the light, hiding in the tunnel, but it seemed content to prowl outside the reach of my campfire. There was an angry buzzing in the distance like a swarm of insects, and the stench of decay licked at my nose.

"Princess Luna?" I called out, but there was no answer.

I strained my neck to look up, and high above me was a hole in the ceiling that exposed the night sky. A twinkle of starlight peeked out from behind the rock, but directly overhead was a crescent moon shrouded by clouds.

I took a moment to examine myself. My hoof and leg were undamaged, and my wings were free and intact behind me. Sighing in relief, I scooted closer to the fire and pulled a blanket tighter over my body. The nightmare was banished, but I was still dreaming. Where was Luna?

The magic surge I felt seemed like hers, but it had originated from myself. It had always washed over the dreamscape like a tidal wave or a gale, but this time, it exploded outward from within me. Somehow, I had tapped into Princess Luna's dream magic. Now that I knew what to look for, I closed my eyes and felt the distant tether to the cosmic forces I had once shared with her.

When Celestia, Luna, and Cadance gave me their magic before my battle with Tirek, the power also came with a tenuous connection to the forces they were bonded with. The power of the sun and moon rested on my horn, including authority over dreams. I had thought that connection severed when I lost the magic, but perhaps it was still there, just lying dormant. My alicorn magic roiled within me, but I felt it returning to its placid state as I grew calmer.

This wasn't something I could do very often, but I was glad that it was an option available to me. If I could get my horn free, I could draw on a sliver of energy from the sun or moon. I wasn't sure what to do with it when I had it, but I knew I could think of something when the time came.

I settled down in front of the fire and thought. The shadows writhed and churned at the edge of my vision, and the strange sounds continued for the rest of the night.

I awoke in the cell. The first thing I noticed was the deep soreness that permeated my body, but the second was that the stabbing pain in my fetlock had faded to a dull ache. Opening my eyes, I was greeted by the same darkness, illuminated by a single dim lantern, that had been my companion for the last three days.

Three days of consciousness with Celestia knew how many days prior in a drug-induced coma. Three days of seeing neither the sun nor my friends. Approximately one hour from now, the guards will bring us our daily ration of cold mushroom broth, which would barely fill me under normal circumstances. Then came the work – work designed to tire and humiliate us.

I took a shaky breath, wiped away a tear, and wondered what tasks they would give me today. Hopefully, I could explore more of the compound. If I was going to escape, I needed to gain a better lay of the land. We needed supplies, food, water, and something to carry it in, but most importantly, I needed a way to remove this horn ring. Access to my magic was a game changer. After that, I needed my saddlebags. They had my spellbook and my copy of Dawnfinder's Promptuary of the Dark. Hopefully, the thestrals had kept them…

I set the thought aside and stretched out my hooves. A twinge of pain shot up my injured leg, and I winced. It wasn't debilitating, but my fetlock was still tender. I needed to be careful walking on it for the next couple of days, though I had expected it to hurt a lot more than it did. Maybe it wasn't as bad as I thought?

Claws scraped against stone, and something moved to my right. I whipped my head around and saw a large shape sitting beside me. The creature was nearly twice my height, even in a sitting position. Long arms, ending in clawed hands, rested lazily on its knees. Manacles and chains, similar to my own, hung from its wrists and clinked as the creature shifted. An ursine head tilted to look at me, and as I saw the lantern light blazing in one of its vast, dark pupils, I knew the darkness held no hindrance to it.

The creature, the quaggoth, rose to its feet. Chains clattered as it moved, and its head brushed the ceiling. I trembled as I found myself standing, ready to bolt, but my legs didn't obey me. Frozen in fear, my heart pounding, I stared at the creature. How long had it been there, watching me? How did it sneak up so close?

It moved, and I flinched away, ready for a blow, but it never came. I opened my eyes, blinked, and stared. The quaggoth had dropped to both knees and prostrated on the ground before me with its forehead in the dirt. A long moment passed, and the creature climbed into a crouching position.

Something moved behind the quaggoth, and I blinked as Stool's diminutive frame shuffled from behind him. The myconid sprout stepped between us, spraying a cloud of rapport spores that tickled my nose and made my head buzz, before saddling up beside me.

"Sorry, Twilight." Stool hung his stalk. "He just kind of picked me up and carried me over here. I think he wanted to talk to you."

I shifted my gaze from Sprout to the quaggoth. It sat there silently and watched me with an eerie calmness. My throat clenched, and I steeled myself with a slow breath before meeting the creature's eyes.

"Who are you?"

"I am Prince Derendil, Your Highness," the quaggoth replied. His mind felt strange as it brushed against my consciousness. It felt like a calm meadow, but the silence that filled it was the hush before a stampede or a thunderstorm. "I regret coming before you in this crude form, but I humbly beseech thee for aid. You see, I hail from the Kingdom of Nelrindenvane, and I was afflicted by a terrible curse that has stolen both my body and my home."

I frowned and tilted my head in confusion. "I'm sorry, but I don't think I've ever heard of this 'Nelrindenvane.' It sounds deerish, though. Can you elaborate on this curse?"

"Wise indeed, Your Highness," Derendil nodded. "It is, in fact, deerish. I was once the crowned prince of Nelrindenvane in the High Forest, a distant land from Equestria. I was, in fact, a deer, but my crown was usurped by an evil wizard who cursed me into the monstrous form you see before you now. He exiled me, and in my wanderings I was enslaved to these denevér."

The quaggoth, this Prince Derendil, slumped dejectedly and covered his face with his giant paws. This was the first I had heard of this Nelrindenvane or the High Forest, but Equis was a massive place, and ponies knew aggravatingly little of things beyond Equestria. I wasn't an expert in quaggoth body language, or of deer, for that matter. The Everfree deer rarely left their forest, and I had only interacted with them once. However, I couldn't sense any lie from the deer-turned-quaggoth.

I lifted a hoof, hesitated, and patted Derendil's leg.

"I'm sorry that happened to you, but what do you need me for?"

Derendil wiped a tear from his eye, sniffed, and sat straight.

"Ponies are well known for their magical abilities. I would petition you for your aid in removing this curse. I, and my kingdom, would forever be indebted to you, Your Highness."

[Twilight makes an Arcana check: 18+9=27]

"Well…" I paused and thought. "It would depend on the nature of your curse. There are multiple ways to transform somepony, or somedeer in this case, into something else, though it's rarely permanent. Your soul remembers who you are and what your body looks like, and it will generally fight against transmutation magic like that. Permanent transmutation is very powerful magic and is very rare, and breaking a spell like that is out of my power… at least, here and now."

"What must be done?!" Derendil almost shouted his thoughts as he brought himself to my eye level. There was a desperate eagerness in those wide pupils. I leaned away from his overwhelming presence, ears splayed back.

"W-well, right now I don't have access to the kind of magic to break that kind of transmutation, but I know where I can find it. The other Princesses would know how to do it, I'm sure, or one of the Master Arcanists at the Tower of Magic in Canterlot."

"So we must…?"

"Yes. I would need to take you to Equestria and have you looked at."

"Which means," he leaned back and clenched his jaw. I heard a low growl and grinding teeth that set my fur prickling. "We must escape from this prison, and I must endure this wretched form for a while longer until I see the sun-kissed land of Equestria. Very well, then I propose an alliance between your House and mine, Your Highness. Swear to me that you will break my curse, and I shall be your sword and shield in this cursed land."

I blinked, surprised, and chewed on the offer. Fortune or Harmony smiled on me today, but I was wary. Derendil was trapped in an alien body that possessed very aggressive instincts if my experience with quaggoths had been indicative of the species so far. I knew that violence was most likely inevitable to escape this place, but I was loathe to resort to bloodshed. The denevér might have been misguided or evil, but they were still ponies. They were still living, breathing creatures.

However, I was just one mare surrounded by enemies in a strange land. Though I hated the idea and didn't want to dwell on it, I might be forced to make some hard decisions to get home. No, I decided. It wouldn't come to that. I needed friends and allies, but I needed to keep my hooves unstained.

"I will do what I can, but I ask that you avoid killing anypony when we try to escape."

"That will be difficult," Derendil tilted his head, "and if any creature deserved death it would be these foul denevér."

"They're still ponies!" I stomped my good hoof. "If we are to work together, there won't be any killing."

"We might not be able to help it," he growled.

"We'll cross that bridge when we get there, but it's my job as a Princess - as an alicorn - to look after all ponykind, and that includes these misguided thestrals. I won't come back to Equestria a murderer!"

"Fine! I will do my best to avoid killing any of these vermin, but I will do what I must to survive if we're cornered."

"I suppose that's all I can ask." I sighed. "Very well. I, Princess Twilight Sparkle, promise to help you break your curse in exchange for you help escaping the Underdark; cross my heart, hope to fly, stick a cupcake in my ey-Owe!"

I rubbed my eye and cursed my lack of depth perception as Derendil tilted his head inquisitively at the ritual. I was sure I'd see a raised eyebrow if there was more light.

"It's a custom from my home in Ponyville," I explained, "called a Pinkie Promise. No one breaks a Pinkie Promise lightily."

Derendil nodded solemnly and repeated the motions. We ended the ritual with a hoofbump, or rather his fist against my hoof, and I smiled at my new unlikely friend. The moment was spoiled by a knocking at our cell door. Breakfast had come a bit early today, it seemed, or I had slept longer than I thought.

We shuffled our way towards the line by the door, and I did it with a new life in my step. I had the beginnings of a plan in my mind and new friends to help me accomplish it. If nothing unexpected happened, we'd be out of this Tartarus hole.

Author's Note

I got flex that Horror tag a bit in this chapter, but Twilight now has a new and unlikely ally. Remember to upvote and leave a comment below!