It should have been dark in the tree once the entrance closed, but Faye had no need of her bracelet. The crystals around her gave off a soft luminescence, evenly bathing the corridor around her in a clear, even light.
She was in a short entry hall that gave way to a circular room, entirely sculpted from opaque, diamond-like crystal. The floor was made up of tiles, each decorated with an alternating geometric pattern that seemed to be made from crystals with different internal structures, even though they were cohesive and bonded together. It looked like something an equine architect would design, but she - as an accomplished scholar of ether crystals and all things related to them - had absolutely no idea how they could have formed.
The walls and ceiling held to an equal standard of unearthly craftsponyship, with microscopic artwork running in continuous lines up and down the slender support columns, barely the width of a mare's barrel, and along a circle inside the outer rim of the roof. All of it showed no signs of ever being worked, as if someone had designed it and then conjured it into existence, exactly the way they intended it to be.
"Sweet Celestia, this design is gorgeous," Rarity breathed, wandering toward the middle of the room with her neck craned. "Do all Crystal Palaces look like this?"
"No," Starlight answered. "Well... Sort of. Most of them are covered in a chalky film that probably built up over time. The only one I've seen without it has been in the Griffon Empire, presumably because Garsheeva lived there to keep it clean."
"So you're saying someone lives here, too?" Applejack looked warily around.
"Well, this is underneath the Princesses' old castle," Twilight pointed out. "They might have cleaned it. And maybe Celestia came back to keep it this way after that castle was abandoned. Or maybe these are just so old that a thousand years isn't enough time for that film to accumulate."
The room had alcoves all along its sides, though they weren't evenly spaced. Five in total, all spaced within the third of the room opposite the entrance, they were modestly deep, each one containing an ornamental pillar engraved with one of the special talents of Twilight's friends. Twilight's own talent was depicted, instead, above the door everyone had just entered through.
"I wonder if each one of these points to one of the other Crystal Palaces," Fluttershy mused, walking toward the alcove with her own talent, directly opposite from the entrance.
"That's my idea," Starlight said. "So, any of you want to take a guess at how to proceed from here?"
"Well, I don't see any obvious exits," Applejack observed. "Maybe we all go stand by our pillars?"
Twilight's horn was glowing. "...There's an empty shaft under the middle of the room. See this circle here, on the floor? This is an elevator. But how do we activate it?"
"You've got a spell for that?" Corsica raised an eyebrow. "Sounds handy."
Twilight shrugged. "Well, Starlight gave me the idea for it. All you do is make your telekinesis as big as you can, then try to lightly grab the area around you and see where you meet resistance and where you don't."
Starlight looked slightly sheepish, but Corsica looked intrigued. "Huh. I'll have to remember that one."
"Hey, I found something!" Pinkie Pie called from a wall near the entrance. "It's a mysterious wall whachamahoozit!"
"Like a switch?" Rainbow flapped over, and everyone else followed suit.
In a shallow compartment on the wall was a ring of crystal about the size of a stallion's hoof, attached by narrow crystal filaments to the compartment's top and bottom, like a gimbal. It was clearly functional, but as to how, Faye couldn't say.
Corsica, Twilight and her friends squinted at it, trying unsuccessfully to turn it or stick a hoof inside it, clearly having no idea what it was. Starlight watched them with a demeanor that suggested she already knew what it was for, but wanted to let them figure it out for themselves before stepping in to help.
Seigetsu and Nanzanaya looked like they knew something, but had far less altruistic reasons for keeping their silence.
"Well, it sure looks functional," Twilight said, stepping back after a minute to scratch her head. "But it's clearly not mechanical, and I can't detect anything magical about it, either. At least, nothing more magical than the rest of this room."
"Yeah, I'm stumped." Rainbow shrugged. "Don't remember anything like this in your stories, Starlight. Unless it was from before the part where I started listening?"
Starlight nodded. "See if this jogs your memory." She pulled out a two-pronged stick that looked vaguely like a magic scepter - where she had been keeping it, Faye had no idea.
"Where where you keeping that?" Seigetsu asked, suspicious.
Starlight shrugged at her. "Magic."
Rarity cleared her throat. "Forgive me if I'm missing something obvious, but what does that thing have to do with this, as Pinkie put it, mysterious wall whachamahoozit?"
Rainbow scratched her head. "...Yeah, I got nothing."
Twilight, though was staring back and forth between the stick and the ring in the wall. "If I'm wrong about this, I'm going to look ridiculous. But are you saying these have the same activation mechanism?"
Starlight looked at her, betraying no intent. Seigetsu looked confused.
Twilight stepped closer to wall, swung her hips, and touched the ring with her special talent.
There was a brief glow, and a sound of energy accumulating. And when Twilight stepped back, a copy of her special talent was there, floating in the middle of the ring.
"What!?" Rainbow burst out. "How were we supposed to figure that out?"
"More importantly, what just happened?" Applejack circled Twilight, taking a close look at both of her flanks. "Your cutie mark's still here, but it's also there..."
"Forgive me if the leap of logic you just made looks tenuous to me, Twilight," Rarity began. "But to an outside observer like our friends here, it must be completely unfathomable. Might it be prudent to get everyone together on the same page?"
Seigetsu was looking back and forth between the ring in the wall and Starlight, who no longer held any sticks. "Would you mind if I had a closer look at that object you produced?"
Twilight glanced at Starlight as well.
Starlight took a deep breath. "Much as I'd like to repeat a week-long story for the benefit of all involved, we are technically on a schedule, here. I don't want to stop you from enjoying the puzzles, but if we try to ensure everyone is approaching them with exactly the same starting knowledge, we'll be here forever."
"Forget why she tried it, what did it actually do?" Corsica asked, leaning against a pillar and watching the proceedings.
"Well, if it works anything like I'm expecting..." Twilight closed her eyes and focused. With a slight rumble, the circle in the center of the floor shifted, descending a bit before coming back up.
"Yep," Twilight said, the circle moving again. "It lets me control the elevator."
"I know we can't spend too much time on this, Starlight," Rarity cut in. "But you talk like you already knew the answer. Can't we get even the slightest hint as to how you figured it out?"
Starlight shook her head. "Just spent enough time here that eventually I got it by accident. For a while, this was where I went when I needed to be alone with my thoughts."
Twilight gave her a look that seemed to say if you don't want to say it, you can just be up front with that.
The group eventually stopped dawdling and gathered on the elevator platform, which proved to be a bit of a tight squeeze. Faye instinctively stood next to Corsica on the way down.
It was a short descent, only one floor until the bottom. The new room was roughly rectangular and furnished like a living space, with a light fixture on the roof that was useless when the whole place glowed and a crystal couch with crystal cushions that were hard as stone. All the doors in the room were closed, but Twilight looked at one, and it opened of its own accord.
"Huh," she said, stepping off the elevator. "I guess that ring controls more than just the elevator in this place."
Twilight opened all the doors, and the group spread out to explore. Faye followed Nanzanaya, and Corsica and Seigetsu followed her.
The room she found herself in was clearly a bedroom, with a dresser and a nightstand and a four-poster, featuring a mattress made of hard crystal and also pillows and blankets made of crystal that were part of the mattress and couldn't be removed. The elegance of the architecture was preserved from the room above, with geometric decorations where the walls met the ceiling and patterns on the floor, but this was clearly supposed to be some kind of home. The bedstand even had another alcove with a crystal ring, this one already furnished with a copy of Twilight's special talent.
Most interestingly, the room had a floor-to-ceiling window that emerged onto what might have been a balcony. It was hard to tell, though, because past it was plain old stone.
"We really are in a buried building," Corsica remarked.
"One designed for habitation," Nanzanaya added. "You see now how it is not so farfetched that my own people live in the tower left behind when one of these dies."
"Assuming you like hard pillows," Corsica muttered, trying and failing to dislodge the ones on the bed.
Seigetsu gave Nanzanaya a curious look. "Does your own home have the same ring technology that was just employed by Princess Twilight?"
Nanzanaya gestured to the ring in the nightstand. "These? Nope. Not just sitting around, at least."
Faye walked back to the main room and explored several others. There was a kitchen, more bedrooms, and several rooms that seemed to have no set function. Most of them had another ring alcove, usually placed out of the way and all already populated by Twilight's special talent. If this was a living space, it was a generously-sized one, probably bigger than Corsica and Graygarden's apartment in Icereach. Starlight, for her part, sat on the crystal couch and waited for everyone to explore.
"So, you've been down at least this far, I'm guessing?" Twilight asked, stopping next to her after checking several rooms.
Starlight nodded. "I've explored this level, but this is the deepest I've gone. That door right there is the way forward." She pointed at a slightly more ornamental door that hadn't been opened yet. "If you're wondering why this place is the way it is... Maybe it's always been like this. Or maybe the flame just realized that I needed somewhere to stay."
"You lived here?" Rainbow asked, emerging from another doorway.
"Not all the time," Starlight said. "But I couldn't just stay in Ponyville itself while... you know."
Faye filed this away for later. It was hard to tell for sure, because Starlight was touchy about her history in the north, but she didn't seem to like talking much about what she had done in the two decades between then and now, either.
"Well, let's keep going," Twilight said, opening the bigger door and leading the way.
Beyond it was a long, straight corridor with identical, evenly-spaced doors covering both walls. At one distant end was another window showing a flat sheet of rock. At the other, the hallway seemed to open out into a bigger space.
Twilight frowned at the other doors. "Weird. I can't open any of these ones. But I don't see any more rings?"
"They're all the same as this one," Rarity mused. "Perhaps we're inside a hotel or apartment complex, the kind you see in Manehattan?"
"More likely an underground housing bloc," Corsica said. "Icereach housing looked exactly like this, except concrete instead of crystal."
"Why would an underground Crystal Palace have housing?" Rainbow asked. "It's not like anyone ever comes down here. And it's not even good housing, either. I'd rather sleep on the ground than that bed."
Applejack nodded. "It's like someone took their idea of what a place like this was supposed to be, and then made it out of all the wrong materials. Look at the Crystal Empire. They've got real furniture."
"Well, better get a move on if we want to find out!" Pinkie spun around three times as if picking a direction at random, and then started toward the open room at the end opposite the window.
That room turned out to be a small lobby akin to the holding room in the Crystal Empire where Faye first met Nanzanaya. It even had potted plants as decorations. Like the cushions on the chairs, though, the pots and soil and plants themselves were all made of crystal. There were even framed paintings decorating some of the walls, but their different colors hadn't translated well to crystallization and they were impossible to make out.
There were also four cylindrical elevator shafts with transparent walls, each one sporting an empty crystal ring next to its doors. Further beyond was a grand switchback staircase. Faye took a peek over the railing, and several others moved to join her.
They were at the top floor. At least thirty more stretched out below them.
"Maybe we should take the elevator..." Twilight suggested, as Faye shook off just a hint of vertigo.
"Anyone else want to give these ring things a try?" Applejack asked, gesturing to the ones by the elevators. "I guess it's obvious what these ones do."
"Me!" Rainbow Dash was fastest, flying over and giving a ring an eager butt-bump. It looked slightly awkward - the ring's alcove wasn't perfectly positioned to be hit by a pony's hips, a bit too high and a bit too recessed. And while it was far from impossible to use, Faye found herself wondering why no one had thought of short foals and less-mobile elders in the design of such powerful technology.
As before, Rainbow's special talent lingered in the ring, a perfect copy shimmering in midair. Moments later, an elevator whisked smoothly to a stop, and the doors slid open.
"Wow." Rainbow blinked at it. "That was surprisingly intuitive. It's like it could read my mind."
"That might not be far from what's happening," Starlight said. "Anyway, this is as far as I've ever gone, myself. Beyond here, I'm as blind as you."
Everyone nodded. This elevator was much bigger than the one inside the living space, and everyone fit inside it with room to spare. The door shut, and it began to smoothly descend.
Many floors passed, each one showing an identical lobby through the transparent walls, with slight variations in decoration and seating but the same architectural plan. If this was aboveground, it would be a tower... and an impressive one, if the progression on Rarity's expressions was anything to go by.
"How tall do you think this is?" Corsica mused, echoing what probably everyone was thinking. "Same as they look when aboveground, just buried?
Starlight shrugged. "Never seen one, so I couldn't say. I don't know how far above ether level Ponyville is, either. Usually, the entrances to the Crystal Palaces are buried deep underground, but this one was near the surface."
Eventually, the elevator stopped in a lobby that was much grander than the others. The room Faye emerged in was an alcove off the side of an immense atrium at least three stories tall, with angular support columns that seemed to invoke sun rays at dawn. Crystal fountains along the walls bubbled with starry liquid, interspersed between reception desks, benches, and larger doors leading off to the sides.
Also, it wasn't uninhabited.
More than a dozen ponies populated the room, some staffing desks, others wandering around or simply waiting on benches. Crystal ponies, it looked like... except the more Faye looked, the more she realized they weren't that, either.
The Crystal Empire's ponies had coats that glittered like crystal, but were clearly still flesh and blood. These crystal ponies were more like golems, semi-transparent and completely composed of crystals that seemed to rapidly re-grow and break down at the joints when they moved. And, disturbingly, none of them had faces.
No muzzles. No mouths. No eyes. No ears. Manes and tails, yes. But no faces.
"What the...?" Applejack stared. "Are those ponies? Those things are creeping me out."
"Oh my," Fluttershy murmured.
"Hey!" Rainbow immediately flew up to one, hovering in a circle around it as it walked. "Hey, you!"
It didn't react to her whatsoever.
Twilight stared at Starlight. "You definitely didn't mention other Crystal Palaces having something like this."
"That's because they didn't," Starlight said, taking a few steps forward. "Are they... ponies?"
"They look like rocks," Pinkie remarked. "I've never heard of rocks pretending to be ponies before, but who am I to tell a rock what it can or can't do with its life?"
Rainbow winged her way back. "Well, they don't seem hostile? Or to notice us at all. But they're clearly doing something?" She pointed to one automaton, which seemed to be having a wordless conversation with another behind a desk, before leaving through one of the doors to the side.
"As fascinating as these things are," Rarity warned, "something tells me you're all too busy looking at them to look at the entrance over there."
Faye looked. One wall of the building was broken up into pillars and arches that created a row of open-air exits. And unlike the ones above, these were actually open air: instead of rock on the other side, there was empty space and, in the distance, more crystals. It was hard to tell how big the other side was from this distance, or what was in it, but it was clearly bigger than their current room.
"Well, let's go check it out?" Twilight led the way, taking the group close past one of the faceless ponies on her way to the arches.
"Wow," the automaton said as Faye neared it. "I just walked past, like, a dozen ponies who all have faces. Each and every one. And there's a civilized monster with them, too! So wild... You don't see something like that every day!"
"Excuse me?" Twilight balked at it. Starlight also jumped a little, but everyone else in the group looked more surprised at Twilight's outburst than at the faceless pony. And the faceless pony hadn't changed its demeanor at all, still walking the same path it was walking before.
For that matter... how had it spoken? It didn't have a mouth. Faye had heard plenty of telepathic chatter in her mind before, not least when speaking with Halcyon. This... might have been that? But it sure felt a whole lot more like natural speech than having something injected into her thoughts.
"Twilight?" Rainbow tilted her head at Twilight.
Twilight gave her a look. "You mean you didn't hear that?"
"Hear what, exactly?" Rarity asked.
"A better question is, who did hear it?" Starlight asked, glancing at Faye, Corsica, Nanzanaya and Seigetsu. "Any of you?"
Faye nodded. The other three looked confused.
"Would someone mind explaining what we're supposed to be hearing?" Applejack pressed.
As Twilight launched into an explanation of what Faye had already heard, Corsica stepped closer. "Hey," she whispered in Faye's ear.
"What is it?"
"I didn't hear whatever this is about. And I never saw anything like that magic ring before, either," Corsica muttered under her breath. "Tell me if I'm just being jealous, but the way they're all reacting to all these things makes it feel like they've never been in a situation like Ironridge before. You know, where things are happening too fast for you to verify the integrity of every bit of ground you step on. And I want to be happy for them, but it's worrying me about how much help they'll be."
Faye squeezed her eyes shut. "Maybe not the thing I'd prefer to be worrying about right now."
"In other words, it bothers you, too." Corsica straightened up and left her alone.
Corsica's words stuck in Faye's head and wouldn't let go, though, so Faye stepped away from the group, making her way to the arches at the building's entrance. Beyond them was a broad plaza, and the moment she set hoof on it, she was outside.
Far, far above, a cavernous cave ceiling soared, bathed from below in the glow of innumerable crystals. Ahead was building after building, an entire skyline of crystal towers, each with its own architectural flair yet blending together in a harmonious style, elevated crystal walkways winding and weaving between them. There were low-slung domes, elevated towers built atop squat, sturdy bases, spires and windows glowing with light. The buildings rose together in the distance, clustering together into a single, monolithic structure at the center of everything, a grand underground capitol for a grand underground city.
To call this a palace would be a gross misrepresentation. It was a metropolis.
With a footprint at least the size of Ironridge and a skyline infinitely more vertical, Faye tried and repeatedly failed to estimate how many ponies this city could hold. A million? Ten? Twenty? Ironridge was the north's most populous city, and its population was in the lower hundreds of thousands. The emotional core she had felt from the surface was now all around her, emanating from every crystal and every building, and yet she could feel it the strongest yet further down, coming from the colossal complex at the city's center.
She walked to the edge of the plaza and looked over the railing, several elevated walkways branching off from it and winding around the city. Below, her tower kept on going, with a bigger footprint as it descended, all the way to a second layer of streets that seemed to be suspended in the night sky.
The ether river. Looking back up at where her tower disappeared into the cave ceiling, she was perhaps halfway down.
Faye lit her bracelet just a little, expanding her senses. The radiance coming from the center of the city was blinding, and the crystal around her offered little respite. The longer she stayed in control, the more the lights she saw around other ponies felt normal, fading into the background of her perception - the same lights that Halcyon perceived as stars in the distance when their memories were closely entwined while passing control. But now, Faye had to consciously block them out to avoid being instantly overwhelmed.
She had wanted to see if she could sense any more constructs amid the glow of the crystals. The answer she got felt more like the city itself was alive.
A faceless pony walked past her, coming from one of the bridges on its way through the arched entrance. Faye stood where she was, waiting to see if it would have anything to say.
"My wife has been so distant lately," the pony said as it passed by. "Always thought I was lucky, marrying someone so smart. You think she's met someone else at that new job of hers? I swear, can't give her so much as a 'how was your day?' without getting an earful of tech jargon. It's passive-aggressive, is what it is..."
Faye frowned after it, but it kept on walking without any further acknowledgement of her presence. These things had families, huh? And family issues. That they talked about to complete and total strangers without even checking to see if they had been heard.
How bizarre.
A commotion behind her heralded the arrival of everyone else on the balcony. Faye tuned them out as well as they ogled the cityscape, concentrating on herself instead, trying to find a balance where she could feel this place without getting overwhelmed. As she was, it was hard to even untangle the cloud of emotions flowing up through the crystals from the city center: sadness and longing, solemnity, duty and grief.
"Hey, Starlight?" Rainbow's voice jolted her back to reality. "This place wouldn't happen to be that one super ancient world from your story, would it? Indus?"
Faye's ears twitched. She knew that word.
Starlight shook her head. "I doubt it. Indus itself is supposed to be long dead and gone. It is a place that mortals can still go, if they try hard enough - the Griffon Empire sent an expedition there once, over two thousand years ago. But it's the kind of place that would take an expedition backed by a powerful nation, or goddess powers, to reach. Getting here, ourselves? It feels too easy for it to be that. This place is definitely a Crystal Palace, just... not like all the others."
"It looks like quite a bit more than a simple palace, darling," Rarity pointed out, echoing Faye's own observation.
"The crystals that make up Crystal Palaces are malleable," Starlight explained. "Usually, their forms are maintained by the intentions of the flames that reside in them. A flame once explained to me that its own palace layout was a memory of the place where it was born. So, the same principle might apply here. This whole city is probably the shape chosen by this palace's flame."
"But why?" Twilight asked. "It's so enormous. When in the world's history would there ever have been enough ponies in one place to build something like this, assuming it is a memory? And if it isn't, what would prompt the flame to imagine something like this?"
"Okay, but if it's not Indus itself, what if it's a memory of Indus?" Rainbow suggested.
Starlight shook her head. "I wish I could say."
"And what about the weird faceless ponies?" Rainbow pressed. "Or the magic rings? I don't remember either of those in your stories about the other Crystal Palaces. Seems like this one isn't just different, it's got more going on, too."
Twilight considered this. "Well, my Element has always been different than the others. Maybe this flame has something more to it that the others don't?"
"The only way you're going to find out," Corsica pointed out, "is by getting where you're going."
"Right," Fluttershy agreed. "I can feel the Kindness flame guiding me. It feels more awake than it was before. We're supposed to go that way, toward the big building in the middle."
"Everyone got a good idea of what this building looks like?" Corsica asked, nodding back up at the rocky ceiling. "Hopefully won't be too hard to find again, since it touches the roof, but we could easily get lost in here."
"I'll be able to find it," Starlight promised. "And if we need it, we can always ask the flame for help getting out."
"I have always had a good sense of direction," Seigetsu offered. "You can count on me to find this place again as well."
"Right, then." Twilight nodded, once again leading the group. "Let's be off."
Navigating the city on hoof quickly hammered into Faye's head just how big it really was. Looking down on the skyline from above was one thing, trying to navigate it - especially when the elevated roads kept twisting, and seemed more designed to aesthetically connect individual buildings than to get ponies quickly from one place to another.
This pattern, after the third or fourth detour in an unnecessary direction, led the group to seek a way down to the streets below. While being at the city floor made it harder to see the skyline, and thus harder to navigate, the streets were straighter and progress was faster... and the ether river was right nearby, to boot.
In a space in between two roads, where a park or garden might ostensibly go, there was instead a gap filled with stars, the surface of the ether close enough that you could reach down and touch it. It flowed gently along, crossed by bridges and rippling against the edges of roadways, strewn with purples and blues and greens, galaxies and constellations, every color of the brightest imaginable night sky.
"Such a shame for all this beauty to stay down here where no one ever gets to see it," Rarity lamented, stopping to stare into the ether. "I'm sure we all can agree that turning such a place into a tourist trap would be a travesty, but this is a kind of beauty that not even Canterlot can achieve."
A passing faceless pony stopped and glanced around. "There's so much beauty all around us, and no one ever seems to see it. Such a shame," it said.
Twilight and Starlight gave it funny looks.
"What is it?" Rarity blinked at them. "Did another one say something?"
"It kind of... stole your observation?" Starlight shrugged.
"These things are weird," Twilight muttered. "I can never tell if they actually see us or not! It's like they do and don't, at the same time? Hey!" She waved at the faceless pony. "If you can see me, do something to acknowledge it!"
"Do you ever feel like nobody actually sees you these days?" the faceless pony said to no one in particular, still staring into the ether river. "I feel like that all the time."
Then it shrugged and walked away.
Twilight stared after it in helpless bafflement.
"I'm gonna guess it didn't tell you what you wanted to hear," Rainbow suggested.
Twilight just shook her head. "This defies all logic. There has to be something coherent going on here."
"Maybe something about this place makes them see us as faceless?" Applejack suggested. "And they see us just fine, but... I dunno, have trouble processing that we're trying to interact with them? Maybe?"
Twilight shook her head. "But that first one remarked on us all having faces. Even though it didn't try to interact with us at all."
"You might be overthinking this," Starlight suggested. "It's possible that they're living, thinking creatures that populate this place, sure. But it could also be that they're created by the same power as the rest of this city, whether it's a memory or something else. Maybe the flame wanted a city, and decided it wouldn't be a city without citizens to populate it. And if that's the case, they might not have complex thought processes to interact with, or be capable of embodying more than a single idea."
Twilight frowned.
Faye didn't speak up. On the train, Princess Luna told her she would be better served by seeking answers to her questions in this place... and that meant she believed this underground city had answers waiting to be found. If they wanted to get anywhere, to find more answers than questions, all they had to do was keep moving.