A few minutes passed of slow, cautious treading - careful to scour the whole of the cave for hazards. One minute went by, then the next, then the next. The trio must have been a good way into the system by now, even despite their thoroughly slow pace.
"Huh?" Twilight spoke, glancing at her summoned wisp, flickering like a light losing power.
"ZZzzzzT."
Gone. No light...
Nothing.
"What happened?" Dash hurriedly asked, panicking.
"It just... disappeared." She responded, hope fading in her tone of voice.
"Look." Nyx spoke up. "Keep calm, we'll either just have to wait until someone gets worried and comes down here with a rescue squad, or we make our way back. Even slower this time."
"Bad idea." Dash added. If you've read enough tales of adventures like this, you know never to take any risks.
Despite all hope being sapped out of the group, it appeared as if a flicker of Twilight's magic had returned. A small glow, creeping its way through channels in the cave floor.
"Twilight! Your magic is back!" Dash, excitably stated.
"Uhh..." She responded, a look of perplexion sweeping across her face. "That's not me."
The glow soon showed its source, revealing a route through the cave, a faint sound of crashing water echoing through the cave's tract.
"That sounds close." Nyx commented, taking a stand and preparing to urge the others to follow him.
"Well, it doesn't look like we're going back the other way." Twi said, looking despairingly at the route we had came. "Lead the way, Nyx."
It didn't take long for the sound to visualise itself. An opening, the size of a large house, containing a pool of fluorescent water at the highest point, streams trickling down the path of least resistance, with a plinth standing tall in the dead centre of the subterranean clearing, inbetween the two major streams carving out the floor
"Now this isn't no accidental tremor." Nyx commented, taking in the surroundings.
"Definitely not." Twilight replied, standing next to the human.
"What is this place?" Dash questioned, taking a seat next to the human also.
"Let's find out I guess." Nyx stated, confidently approaching the centre of the opening, stopping only to avoid the forks of water streams.
Carefully evading the water, as he had no idea of its properties, he made his way towards the plinth and had started circling it, examining every part of it, piece by piece. Eventually, Dash and Twi had enough of the tension and flew over to where he was standing.
Atop the rock, there lay a single piece of paper. Well paper may have been a strong word. All that remained was an excerpt from some instructions by the human's calculations.
"Wait five seconds?" Dash confusedly asked. "One... two... three... four-"
"Five..." Nyx, continued. "Well... I'm worried, we heading back now?"
"Yeah." Twilight added. "I'm a little worried too." She then stated, before urging us back into the cave system. "Let's go get Princess Celestia before we so anything else."
CLANK
"WHAT WAS THAT?!?!" Dash screeched, grasping hold of the human and other pony. Soon making the adjustment to act like she was protecting them.
The pool then began to create wave forms, only seen by the overflow spilling onto the floor below. After they had gathered up the group courage to valiantly face whatever was happening. The trio scaled the rocks and took a close glance at the pool. Waves they were, but they appeared symmetrical... unnatural. Frozen half by awe, half by terror, the three witnessed the luminous fluid assemble itself around the plinth, rising up above it, shielding their vision of it.
The crackle of tumbling rocks startled them, but maybe not quite as much as the ceiling caving in, taking one chunk after another, eventually making the whole clearing tremble.
Daylight struck them. At last.
A scaly crack formed in the clearing, causing the loose roofing to clash into the floor below, revealing an ornate pebbled pathway to the outside world. A literal staircase to heaven.
The water sank away into the depths of the clearing, the roof appeared to harden once again. The only differences noticeable being the newly formed pathway and the central rock formation, altered to resemble a mirror. Some rare gems also appeared to have made a home inside the etched structure.
Approaching the mirror-like object, Twi and Dash seemed to have absolutely no clue as to what had happened, or why. To be fair, neither did Nyx. The rock layer inside the object - made to resemble the glass of a mirror - had been engraved. No particular pattern stood out. It looked amorphous. Irregular.
Cracks began to emerge, following the pathway the engraving made, crumbling into a vast nothingness left only as dust on the ground below. What remained had no significance to either Dash or Twilight.
Nyx recognised what he was looking at. There was no way he could get this wrong.
Home.
A distant view of a city. Maybe from the top of a hill. Vehicles lighting up the roads, the hum of the local wildlife, sirens blaring off in the distance. A living breathing view of his old world.
"Nyx?" Twilight asked. "Are you okay?"
"Yeah..." He replied, taking a step back. "It's um... well I recognise it."
"What is it?" Dash pried, edging closer to the stunned human.
Before any answer could be made, the distant rattle of a chariot stole his attention. Yet before they had any time to say 'what in the name of Celestia,' Celestia herself began strutting down the newly formed steps, encouraging a new era of light to move in.
"Princess!!!" Twilight exclaimed, greeting her in mild panic and relief. Nyx and Dash sharing a double glance, mostly of confusion, but some - thankfully - of relief.
"Hello, Princess Twilight." Celestia stated, patting the ecstatic pony on the back with her outstretched wing. "I believe I need to speak to your friend here." She then said, urging me and Dash to approach her with a friendly hoof gesture.
"So." Nyx spoke up. "What's going on here? And how did I just see my home through a stone mirror, portal, pool thing?"
Celestia, giggled innocently yet profound. "I had a feeling you'd ask that." She commented, continuing to giggle while talking. "Well, if you must know. Luna told me about some of the dreams you've been having since you arrived-"
"Wait what?!" Nyx, interrupted. "I thought that she could only see ponies' dreams."
"Apparently not." Celestia replied, once again giggling. "Don't worry, that was the only thing of note she brought up."
"Right." He responded, the small blush emerging on his face dissipating with haste.
"Speaking of, I'd appreciate it if you came to Canterlot to discuss your findings there." The princess exclaimed, drawing attention back to Twilight and Dash. "Well, i'm sure you've all had a tough day so far. Please treat yourself to a lovely day out after your efforts."
"We will, Princess." Twilight answered, before grabbing Dash and gathering her bearings as to where she was in relation to Ponyville.
"So, Nyx." Celestia said, locking eyes with me. "Do you miss your old world?"
"I- uh, wow. That's a hard question." He replied, internally checking his answers before speaking. "I guess so. sometimes I do, sometimes I don't. Loads of good things there, a lot of not-so-good things."
"I assumed as such." Celestia replied with an understanding tone of voice. "Please treat yourself. I can only assume what efforts you've put in today. And with such little time to acclimatise. My sincerest apologises."
"Don't uh, worry about it." He responded, also with an understanding tone. "I'll of course talk to you about today soon enough."
"Farewell, Nyx."
"See you soon, Celestia."
Ascending the stairway, Dash and Twi had waited by the top, their eavesdropping session ending when they heard the footsteps grow too close, careful not to look too suspicious.
"So." Twilight immediately pried. "What was that about?"
"Ah, nope." Nyx, responded abruptly. "I'm going home, relaxing and thinking this all through."
"Aw c'mon!" Dash, begged. Will you at least tell us later?
"Sure."
""Yay!"" The two replied, accompanying the human back onto the nearest usable pathway back towards pony, escorted by a royal guard the whole way back.