To Swim Among A Sea Of Stars

by Estee

Rating: everyone
Tags: Princess Celestia, Slice of Life, Princess Luna, My Little Pony: Friendship is Magic
Length: 7872

It can be hard for a sibling to perceive matters from the other’s perspective. Getting Celestia to view any part of the world through Luna’s eyes takes special measures. And a lot of water.

They love each other. But they don’t always understand. Centuries of shared time still haven’t been enough for each sister to fully comprehend how the other views the world, and that’s just one of the reasons Celestia and Luna still have fights. And sometimes it’s the smallest, stupidest differences, like how Luna prefers the longest of baths and Celestia doesn’t…

Luna feels that being immersed brings a pony closer to her world. And Celestia doesn’t understand.

Some lessons require special measures. Along with a lot of water.

And tiles. There’s definitely going to be tiles.

(Now with author Patreon, SubscribeStar, and Ko-Fi pages.)

Published 2023-09-23 18:30:01 UTC
Last updated 2023-09-23 18:30:01 UTC

Mare Cognitum

It was the sort of stupid, petty sibling fight where you not only thought of what had to be the perfect rejoinder two hours after the fact, but had to immediately seek out the other combatant. The ideal comeback had to be delivered personally. Plus it clearly wasn’t an idiotic attempt to extend the battle if the final verbal strike would allow Celestia to win.

Perhaps it would have been possible to blame the national budget. Celestia wasn’t necessarily bad at math — any more. It just didn’t come naturally to her. She treated the world of numbers as the sort of foreign language for which a single stray diphthong altered entire paragraphs: it could be studied, and it was possible to gain some degree of skill — but the older sibling was constantly on guard for the one stray integer which would turn numerical diplomacy into all-out accounting war.

Luna, by contrast, was naturally fluent. She could casually dive into tides of imaginary numbers and come out surfing on fractals. She also didn’t seem to understand how utterly annoying that was. And when it came to writing out that winter’s initial draft for the nation’s budget…

Celestia felt that experience meant something. An extra ten centuries of figuring out where the money needed to go — that had to provide some degree of benefit. And Luna had been in… abeyance. She hadn’t been present for the founding of what had to be eighty percent of the current programs. The younger hadn’t gone through the circumstances which had created them, didn’t recognize how necessary they were…

The elder felt it was around eighty percent. Verifying that would require asking somepony, and that somepony could absolutely not be Luna. There would presumably be a day when having the younger sister correct her work would not be fundamentally irritating and after nearly thirteen centuries of life, it wasn’t getting any closer.

They’d been working on the budget. Celestia had tried to explain it. Luna simply insisted on doing what she described as fixing it. And there were ways in which they were both right, but… it was that kind of argument. Four hours of calculus-hosted misery had brought them to the point where neither was about to give over so much as a mane strand’s width, they’d called it quits for the cycle because that was slightly easier than declaring war, left the debate room by separate exits, and then Luna had called back one final select sentence over a star-streaming tail.

Celestia had fumed for two hours.

Then she’d thought of a comeback. And since she was almost completely certain of just where her sister would be…

She’d been right. (Of course she was right. She was right about the budget, and now she’d been just as perceptive about this as well. The elder had doubly won.) And she’d delivered her perfect sentence, the ideal phrase, what had to be a comet-collapsing comeback into the acoustics provided by marble walls and gently-rippling water, in a room the size of a pool.

It had been perfect.

And Luna was just… looking at her. Placidly, with the starscape of mane and tail fully stable. Not reacting at all.

…well, technically, she did drift slightly to the left. But that was probably just the current.

“Truly?” the younger finally asked. (It took some voice projection for the casual inquiry to fully reach Celestia, and the snideness lost nothing from the voyage to a distant shore.) “Some two hours since we parted, and that was the best you could do?”

Celestia fumed —

“— do you mind, sister?” Luna sharply called out. “It takes a considerable amount of time to fill this. Just as much would be required to refill it. And only one of us is comfortable when standing within the lesser form of liquid fire.”

The elder tried to glare at her sibling, found the lightly-bobbing dark blue form becoming indistinct in fast-rising mist.

It took several deep breaths to get it all under control. But the temperature began to drop, and water condensed on marble walls.

She’d been fuming, and done so in such a manner as to turn her immediate vicinity into a sauna. Any humidity which came into contact with that level of frustration tended to become steam.

(She hadn’t noticed the heat. She almost never did.)

Eventually, the younger shrugged. Dense, soaked fur rubbed against itself, and a few droplets were squeezed out.

“So if that was truly your final volley,” Luna said, “then I would ask you to leave me to my bath. We can resume this on the next cycle. Perhaps by then, you would be willing to admit that I am right —“

“We could do this here,” Celestia tightly declared. “I can stay up for a while.” It was winter, and the Solar shift was technically somewhat shorter. Not that it usually mattered.

“I am bathing.” Words which weren’t quite as calm, and the elder spotted a new potential angle of attack.

“You could get out.”

“I. Am. Bathing.” And now there were tiny needles of ice floating in the water. In terms of visibly breaking Luna’s calm, this represented significant progress.

“For what?” Celestia inquired, and managed to get her tones into the lilt of the false tease. “The last two hours? And you still don’t feel clean? Maybe that’s because you know you’re in the wrong about that last cut. Maybe you can’t admit it, but the guilt just won’t wash away…”

Luna glared at her. Celestia gently smiled. The water tried to ripple, and found itself having to cross miniature floes. The undertides would probably take care of those.

The room was the size of a pool because that was how Luna bathed. She used water in tremendous quantities, to the point where the palace’s current plumbing solution for the massive draw was tapping into a nearby lake. It was possible to host Games swimming events in Luna’s bath. However, the trials would have to be held somewhere else, because the least skilled amateurs would never be able to cross the distance without tiring.

The room was marble, because so much of the palace was marble. (Water dripped oddly from marble, added irregular punctuation marks to any argument.) The pool was sunken and even with the strength of stone in play, it had taken some major engineering feats to make sure everything could take the weight. And Luna was just floating there, because a stressful night could leave her floating for hours. Eventually, she would drift beneath the raised curving tubes of metal and trigger a rinsing spray, although most ponies might have described it as a four-hose deluge.

She might consider getting out after that.

Might.

“Sister,” Luna finally said, “this may be a question of perspective.”

“Yes,” Celestia replied, careful to keep her voice light. “You can’t see that you’re wrong.”

Silence. Water dripped. Some of it froze to the walls.

It was rare to win a moment of silence from Luna. The elder was starting to feel as if she was on the right track.

“Perhaps if we both rest,” the younger decided. “Recover. A process which, of course, takes a full cycle of Sun and Moon. We can resume after —“

“If you stay in there much longer,” Celestia told her, “you’re going to turn into a seapony.”

Luna’s expression was calm again. But the half-tangible tail lashed, and the water wasn’t quite sure how to react: over, under, through…

“Seaponies do not exist,” Luna eventually stated. “We looked.”

“There’s certain issues in searching for very long,” Celestia reminded her. “Fatal ones.”

“…yes,” the younger finally admitted. “Breathing spells were not particularly advanced at the time, and the modern nights still have difficulties in dealing with the pressure of the depths. Regardless, I feel the mythical realm of Shoobedoo will continue to remain exactly that. Tia, it has been a rather long day and given how long we were debating the budget, ‘day’ is exactly the word I intended. May we please —“

They were sisters. They loved each other, often in spite of everything. (Sometimes because of it.) But they fought, because that was what siblings did. Even after so much time. Perhaps especially after so much time, when true harmony meant that there should never be a final victory.

The elder recognized that, deep down. She knew that her sibling was tired, and that it would be better to start over at another time. Perhaps there was even something in her which recognized that on a few of the budgetary issues, her sister had located legitimate points. Every one of which had only felt everything like a stab.

They loved each other. In spite of, because of: the love was still there. But the chasm of perspective could be impossible to cross. Locked within their own skulls for a lifetime and when those lives had gone on for so very long, the locks could feel endlessly heavy.

They loved each other.
She did her best to remember that.
But emotion wasn’t comprehension.

On some level, she recognized all of it. But it had been a very long day, and she wanted a win.

“Why do you do that?”

It wasn’t so much an extended silence as a rather long pause.

“I am trying to define ‘that’,” Luna finally announced, drifting slightly left and bumping into a tiny iceberg. “A process which will require some time. Unless you care to do it for me?”

“Why do you take to the water so much?” Celestia asked. “Hardly anypony spends this much time in water. Even ponies with marks for sailing stay over it, and swimmers get out sometime. Ponies aren’t naturally meant for water, Luna. So why a giant bath? Why hours of soaking, and…”

Her head tilted several times, allowing the horn to serve as pointer: rinse tubes, the giant inlets, drains which had required two drawers for all of the filed patents. A final pair of head sweeps indicated the full length and breadth of the pool: this required some significant neck movement and a touch of muscle strain.

“…this?”

Silence again, but — a different kind. Luna’s features scrunched with careful thought, and more water fell away.

Celestia watched. The pool was sunken, and that made it easy to look down on her sister. Even easier than usual —

“Natural connection,” the younger concluded. And almost smiled.

The elder thought that over. Twisting pastels shifted into each other, hues blurring across the fuzzed border of confusion,

“…what?”

“Being immersed within water,” Luna steadily voiced, “is much like being immersed within night. And as I am reined to one…”

She did smile. A calm, rather relaxed specimen. One which declared that as far as she was concerned, she’d just answered everything.

Water like night.
So if you remain submerged within either for too long, you drown?

But she didn’t say it, because there were words which should never be part of any little fight. And she knew that to remain eternally under Sun, without change or respite, would be to have her soul burn.

And… Luna seemed to feel she’d solved the impromptu, half-unintended riddle. Celestia was thinking about it, turning the words over in her head again and again as the younger watched, the lathe of thought wasn’t smoothing away the edges and…

I don’t understand.

Which made it feel very much like Luna had just won. And in turn, that meant Celestia had lost.

Again.

Celestia wearily shook her head. The pastel flows slowed their pace, came to a stop. And the elder sister shifted all four legs, forced her wings to remain at the rest position, and — turned away. Began to walk towards the exit, ending what had indeed been a very long day.

“I suppose if I actually understood that,” she wearily said, “I would be that much closer to understanding you.”

There was a sound from behind her. It was a little like a spontaneous six-limbed body spasm and jerk, a lot like water being displaced in all directions, and just slightly like a soft gasp. The gasp was mostly audible in retrospect.

“Truly?”

She also missed the tone of it on first hearing. That half-desperate note of hope.

“Yes,” Celestia replied, not really paying attention to the word. And left.

Ideally, the elder preferred to have some warning for her sister’s plans and with too many prior examples, that would have meant gaining any warning at all. Luna liked to play things close to the regalia, and kept much of it tucked under the sternum plate. She didn’t quite believe that it was easier to gain forgiveness than ask permission: after all, as a full equal in the Diarchy, permission usually wasn’t being sought. But she did feel that the ideal time to explain whatever had just happened was in the aftermath. And besides, informing others about what she was up to might make them feel as if there was a chance to correct her.

So Luna didn’t tell Celestia anything.

But this time, it was because doing so would have spoiled the surprise.

The lesson.

The gift.

They managed to work out the budget. It took three additional cycles, every one of which inflicted its share of little wounds to lick clean. There were a number of compromises, accompanied by multiple small skirmishes. Celestia wound up taking the majority of those victories, and it would take her weeks before she realized that some of them had arisen because her opponent had been somewhat distracted. And afterwards, the battle died down again — but it never completely went away. It arguably couldn’t, because they were sisters. They loved each other, fiercely protected the only remaining fellow survivor, and… they argued. Fought, now and again. Generals in the war of perspective, fighting over access to what often felt like an imaginary piece of common ground.

The cycle-to-cycle operations of governing a nation took over. There would be a little crisis, a minor border tiff, or a law to sign. The Bearers were dispatched twice during Luna’s preparation: once for an afternoon, with the second time requiring five days. The first mission, which had been intended as a diplomatic meet-and-greet, required the majority of the cleanup.

Celestia didn’t know what her sibling was up to. She didn’t realize that Luna was planning anything at all. But she inadvertently spotted the outskirts of the plan, and did so without recognizing what she was seeing.

Luna was traveling. Or rather, she was meeting with escort-capable unicorns: those few who could both teleport and take others with them on the journey. This had actually been (irregularly) going on for some time, because there were far more cities, towns, and settled zones in the nation than had existed prior to abeyance. Being escorted to the new allowed Luna to memorize her own future arrival points. And it was good for Luna to go out into the world again, to meet ponies and give them a chance to learn who she truly was.

(It had been nearly thirteen hundred years. Celestia was still trying to work that last part out.)

So Luna traveled. Taken to another part of the realm in a flash of light, always returning well before Moon-lowering. That was natural. And if she was doing somewhat more of that, then… that was good. Also, time away from the palace represented a chance for a cooling-off period. Obviously easier for Luna…

There was a single slip, and the younger wasn’t the one who made it. Paperwork was passed off to the wrong department, effectively crossing the Lunar/Solar line. Somepony decided Celestia needed to review it, and the elder barely glanced at the unusual material purchase before deciding that Luna was just refurbishing something. (This turned out to be correct.) She sent the invoice back to the proper office, and gave it no more thought than was necessary for scrawling her signature: almost none.

(Her official autograph was a series of elaborate loops. The palace signature was a uniquely-illegible scrawl. It saved time.)

Those were nearly all the clues she received, and she would eventually tell herself that it never could have been enough to assemble a solution. An increased amount of travel, one wandering invoice, and… Luna tended to return from her journeys somewhat cleaner than she had been at departure. Nothing to work with there.

Of course, if she’d been paying real attention, she might have registered that a silver-clad hoof had flipped a few calendar pages, designated a date, and was steadily clearing away Celestia’s evening schedule…

The elder only spotted that part on the night before the gift.

It had been a busy week. (The Bearers had almost been dispatched, and several Guards were aching in their stead.) The sort of period where you didn’t dare to look too far ahead, because you had to fix what was currently in front of you and besides, it was almost courteous to let the more minor problems enjoy their ambush. So Celestia didn’t see that her schedule was partially empty until she was almost right on top of it.

A small flare of sunlight opened the appointment ledger. She saw the blank space. And her first reaction was relief.

It was rare for either sibling to have their full duties end when their shift technically closed. For Luna, this was most true in summer: having less night to work with meant more to do within limited hours. Celestia faced the same issue in winter, and it was ultimately simpler to just divide up the Solar and Lunar staffs equally across the clock. But it was somewhat easier for each of the sisters to operate during the right hours, experiencing too little Sun in the coldest season could make Celestia increasingly irritated…

She usually didn’t want to keep working after the orb was lowered, and the bureaucracy never cared. But there were times when the stars aligned by sheer accident, and did so at a rate of slightly more often than once per thousand years. She was looking at a night off.

Most of her background thoughts during the next day centered around figuring out just what to do with it. Sneaking out to a cinema usually meant asking the owner to gift her with a screen to herself: she was too distracting for the audience otherwise. (She also didn’t like the view from the typical Princess Box, which was far too much off to the side — and to place herself front and center meant everypony for several rows behind her was mostly looking at a great expense of white.) And it could also require ditching her Guards, because she really didn’t need the cinemaphiles among them twitching as they tried to figure out what was and wasn’t considered to be a spoiler.

In theory, there was the chance to do something with Luna — but miraculously-cleared night hours for the elder weren’t going to be echoed in the younger’s schedule. Not unless those had been emptied on purpose —

— which would need more notice, and so wouldn’t happen.

Maybe she could just read. Something other than a legislative composition, intelligence report, or post-Bearer repair expense sheet. There were novels she’d been meaning to catch up on and since the act of reading for pleasure only seemed to summon an interrupting crisis roughly thirty percent of the time, she even got to finish a few.

Then again, when she compared that to the disaster summoning rate of the typical cinema visit…

Sun was lowered, her duties were concluded and at the exact moment Luna intercepted her on the way to Apex Tower, the elder was almost on the verge of a decision.

“Time to yourself, sister?” formed an immediate inquiry as Luna nearly matched hoofsteps on Celestia’s left: the smaller alicorn needed to move a little faster to keep up. Not nearly as much as she once had…

It had clearly been a question, and Celestia carefully considered her options as they moved together across the marble.

She probably doesn’t want my advice on something. They did consult, and fairly frequently — but each had the final word over their own dominions. (Budgeting, which had to cover everything, formed a common battleground.) It still meant that they had to be there for each other, because there had been a very long time when they had not.

The odds that Luna was experiencing the sort of crisis which needed assistance were not zero. The chance of her immediately requesting help were somewhat lower.

She may just be curious.

Celestia couldn’t always be sure. Each knew the other better than any other living pony, but — not perfectly. Love wasn’t understanding, and perspective would always find a way to carve out a dividing chasm.

“Yes,” was safe enough, and formed a natural invitation for Luna to follow up. The younger did.

“As have I,” her sister calmly informed her. “Will you travel with me?”

Celestia’s casual trot began to slow, and did so at an inverse ratio to the rate at which her thoughts were speeding up. Luna continued to match her, if with somewhat less effort.

Rather carefully, “You cleared my schedule.”

With utter calm, “I requested that a few among your staff shift certain meetings. Which took more effort and convincing than I had hoped. They are — rather protective, sister. Not that they seemed to feel I intended harm, but… they do hear the little battles. Sometimes from a rather short distance. And when I would not explain my precise reasoning for the request…” A smooth, traveling shrug, as mane and tail rearranged their respective constellations. “I am simply fortunate as to have been accommodated, in secrecy. Several times over. Will you travel —“

“Why?” was also basic, along with being much shorter than You’re up to something.

Seriously, is any degree of warning too much to ask for?

“Because I have something I wish to give you.” She paused, and feathers awkwardly rustled. “Or rather… I wish to try. I have no way of knowing whether it might succeed. The only mare who can determine success or failure resides within another’s skin.”

“A gift,” Celestia tried. “Which requires travel —“

Luna stopped and in doing so, forced Celestia to match her.

The younger stared up at the older, and dark eyes did not beg. Luna seldom begged. Moon wasn’t known for doing a lot of pleading either.

But each breath was short. They caught in the throat, and nearly blocked the only word there was.

“…please...”

Luna had initiated and directed the teleport: a necessity when the younger was the only one who knew where they were going. It had brought them to the center of an empty gatehouse: one which looked just about like every other gatehouse in the nation because when a structure had to remain forever empty so it could safely serve as a destination for such journeys, there wasn’t a lot of room for decoration. And when they’d stepped out…

There were portions of their nation which Celestia rarely saw. She tried to tour now and again, make sure that the citizenry knew she was truly here as their —

— as one of their rulers. They had to see the Princesses every now and again, if only for reassurance. (Having them see her as a pony was much more difficult.). But still… some areas could suffer a degree of neglect, and the regions which saw the least visits tended to be the most self-sufficient. In this case, the area was known to have a significant monster population. It had been that way for a long time and accordingly, the residents had become rather good at dealing with just about everything themselves. The palace rarely needed to directly intervene, much less assist. And even when Celestia did go on tour… it was generally during the summer.

She hadn’t seen an Eastern Saddlezania winter in decades.

It was an exceptionally cold region, and remained so because the Weather Bureau understood that the locals liked it that way. The area had three primary exports: young adults who’d decided that having grown up there meant they could readily take on the rest of the world, sourced monster parts, and relaxation science.

Living in the Saddlezania region could be stressful. The natives needed to relax. And they did so with such skill that tourists frequently ventured into that territory in order to try out the spas, because it was a beautiful part of the nation and they might as well relax among natural majesty.

Visitors were advised to either stay on the roads or travel with a guide. The most fortunate result for some of those who didn’t was to wind up with a somewhat more urgent need to calm down. A few were placed on treadmills until their legs finally stopped running.

Ponies were advised to use guides, for safety. But the lone travelers on the white-obscured road had each other.

A three-quarters Moon shone down on bare branches and fresh snow. The shadow-coated white crust was steadily broken by eight heavy hooves: Luna sank in a fair distance with each step, while Celestia usually wound up with her hooves compacting semicircles of ice onto the actual road. And it was cold, truly cold, to the point where a normal pony’s breath would frost in front of their snouts and then waft back to freeze eyelashes together — but the travelers were the Lunar and Solar alicorns. One knew the chill of Moon, and required an active effort to simply notice when others might shiver. And Celestia…

She carried Sun’s warmth with her. Always. There were times when she had to keep most of it inside. And she kept telling herself not to melt the road clear, because the locals liked it this way and besides, any moisture which remained in the air would be a thin coating of treacherous black road ice by morning.

Still… it was tempting. One thought, and the sheer amount of steam…

…would be mostly competing with the other sources.

Eastern Saddlezania. Frozen winters and rivers which never knew ice. There was volcanic activity in the area, and most of it was buried deep. The surface saw a few rumbles occasionally, and little more than that. Eruptions were both rare and, unless you were right on top of one, harmless: the earth ponies had set up travelways for the lava, and death flowed well away from life. But the heat went deep, some of the water flowed just close enough to gather a portion, and…

Snow under their hooves. Steam rising from the flow of liquid on their right. Natural hot springs.

Chill and heat, traveling side by side.

“You are rather quiet,” Luna noted. Glanced up, then back: the warm lights of the town were continuing to recede. “Almost unusually so.” Returned her attention to the fainter soft light, about a twentieth-gallop ahead on the road.

“I’m trying to figure out what the gift is,” Celestia admitted. “Especially one which would require coming here.” Carefully, “I thought — a spa evening. But there’s more than a few in Canterlot, and they’re nearly all run by ponies who started here —“

“— somewhat,” Luna calmly interrupted, and dark ears briefly dipped. “Yes. As the setting, at least.”

Melted snow was beginning to soak Celestia’s pasterns: an irritated thought evaporated and dried.

“Because we’ve been stressing each other out,” the elder sighed. “Even with the budget done —“

The only other survivor took a breath. Nearby evergreen needles seemed to bow inwards.

“We do not understand each other.”

Celestia stopped. Snow crunched. A half-tangible tail had a waft of steam pass through.

Luna, who had kept moving for an extra moment, got half a body length ahead. Paused, then looked back.

“Or rather,” she quietly added as Moon’s light reflected from her eyes, “that comprehension is less than perfect. We are very different ponies, Tia. Each tells herself that she knows how the other thinks — but there are times when we are wrong. Still. And each carries the other — but we carry the selves we knew at the start. Impressions which… have not changed. Which cannot change. An older sibling, a younger one. A constant, forever coloring perceptions. And… that through our own eyes. Because we cannot see through each other’s…”

The words had been calm. Perhaps too calm, to the point where something in Celestia was starting to respond with a long-delayed memory of terror. “Luna —“

The left forehoof came up. “— wait, Tia. Please.”

Celestia stopped.

“I still think of you as the mare who existed before — abeyance,” the younger softly managed, and did so as mane-captured stars twisted. “Sometimes… well before that. Because I missed every little alteration which came during the lost time. I missed everything, and…” The dark head dipped. “…being absent to witness those changes is what produces so much of the regret. And yet…”

She looked up into purple eyes. Sighed, and the darker form became perfectly still.

“…if I had been present… one thing might be the same. That I… love you, and tell myself that I know you — but I cannot think as you do. Not every time. I can never be you. I cannot see the world through your eyes…”

Her head went down again, and Celestia stepped forward.

“That’s everypony, Luna.” Wondering if any of the sudden desperation had reached her voice. “Everypony in the world. We’re all trapped in our own heads. Love and friendship is how we get closer to some degree of escape —“

“— empathy,” the younger half-corrected, still gazing at the snow. “Yes. But tonight… I wish to try and offer a gift. That of going further. And I do not know if it can work.” Private stars were beginning to dim. “If… this will let you know something more of me. But… likely for an instant at best. Only you can tell me if it went that far, Tia. Only you…”

The Solar alicorn took a slow breath. The realm’s largest rib cage shifted.

Trust her.

She had to remember that she trusted Luna, because it was just Luna now. The other thing was dead,

“Is it a spell?” Something experimental… trust …which could have all kinds of problems…

Tell me it isn’t a body swap.
I need to hear these words.

The younger looked up. Blinked.

“No,” the dark features voiced, and did so with a faint smile. “And yes.”

And she resumed her trot through the snow. After a moment, Celestia hurried to catch up.

“It’s not a body swap, is it?”

“I am already attempting to achieve the near-impossible,” was rather dry. “That would be going too far. And when it comes to any sort of exchange, I find Starswirl’s previous disaster to be sufficient.”

“It is a spa,” Celestia immediately decided.

“A mineral bath,” Luna corrected.

The building seemed to exist as an enclosed intersection. The central portion had been created by taking several thick, evenly-spaced tree trunks, then using them as the bracing points for a roof and multiple huge panes of glass. (There had been earth ponies involved in the construction, and so all the trees were still alive.) That section rose to four times Celestia’s height, and contained a wide-but-shallow indoor pool. She could clearly see the full extent of it through the glass, with that one light left on. It could easily host at least seventy ponies, and it would take an exceptionally short adult to have the water lap against their jaw.

There were padded, water-absorbent benches around the pool area. A few empty refreshment mugs had been left out for the night — but the juice bar had been fully shut down. The sign above the descending ramp to the left said it went to a sauna, and that was a high-risk enterprise for froth-producing ponies. The right went to a drying room and cooldown track.

Look all the way through the glass, towards the back, and it was possible to see a half-covered section of steaming river. It flowed through that portion of the building, and a rotating gate let ponies reach the outdoor portions. There was also a cold-dip pool, currently unnecessary.

Glass and wood in the center: for Eastern Saddlezania, both would have been reinforced into something closer to steel. But at the sides — smaller enclosures with no glass at all and closed doors, occluded from sight. The sign near the right one claimed a whirlpool bath, whatever that was. The left simply said Clozed For Renovationz. Current Vait: One Day, and it said that because the locals felt that if you spoke that way, then any spelling had to naturally follow.

“I don’t see anypony inside,” Celestia noted.

“There are none,” Luna calmly told her. “Tonight, we are their only clients.” Her horn ignited, and a dark corona flowed forward to interact with the locks.

“So you’re going to teach me about enjoying baths,” Celestia tried her best guess. “Here. And then I might understand you more —“

“— no.”

The door clicked, glowed, and swung open. Luna trotted forward.

“No,” Celestia repeated, carefully following.

Luna glanced back over her tail, and something in the elder waited for withering words —

“Your memories go somewhat deeper than mine,” the younger said — then shrugged. “Two years older, after all. But water was not to be trusted, because — in our youth, what was? Air turning solid when his attention focused, and who knew what water might become? Or… what already lurked within it.”

She went inside, tail flicking meteors against the door frame. After a moment, Celestia joined her.

“There were attacks from the lake,” Celestia admitted. “And the stream. You remember a few.”

“And I also remember that they can no longer occur,” Luna placidly replied. “At least, not in the same ways. But it is more than that.” She began to trot around the rim of the pool, towards the Renovationz sign. “I can but guess, sister, but — I feel that something in you sees water as — fragile. After all, it requires but the lightest touch of your fire to disperse.”

Another glance back. And after a moment, the elder nodded.

“For me,” Luna continued, “it is rather more real.” Paused. “And, should my emotions join with my magic, more solid. So for tonight, Tia… let the water simply be. Let it be, until it barely seems to exist at all.”

Purple eyes blinked. “Luna —“

“— final preparations,” the younger said. “I must arrange the area, as far as I can. Wait here.”

The next door opened, and did so at the same moment when Luna’s horn flared with darkness. An umbra which, in all the world, only she could see within.

Celestia could combat it, of course. Invoke enough of Sun’s light to dispel. But…

Trust her.

The shadows coated the doorway, concealed what was beyond. Luna trotted inside.

It took about five minutes. (Celestia only started to pace during the last two.). And then Luna softly called out “Enter.”

Celestia looked at the little wall of darkness over the entrance. Forced her legs to move, stepped through —

— another pool.
Smaller this time. Maybe fifteen ponies for comfortable capacity. But it’s also deeper.
Slight chill in the room. That’s coming off the water.
And the lights are…
…the water is…
…dark.
The water is glowing with darkness.

This pool was inlaid with a closely-spaced mosaic of dark blue and black tiles: something which finally explained that one stray invoice. The liquid itself seemed to be an exceptionally dark shade, as if it had been taken from the Cerulean Grotto — but that was clearly impossible: any water brought out of the deep place reverted to normal within five minutes: by coincidence, this was the same safety margin for remaining within the cave and recognizing its beauty. After that, the viewing pony would never be able to appreciate anything again.

Celestia could barely see the bottom of the pool, and what she could spot told her that for a normal pony, it was deep. The facility seemed to be built around letting its clients stand safely within water, because ponies made for poor swimmers. With this hollow…

I could probably stand in there. But the water would have been just short of her chin. Back fully covered, and the wings…

Are those little holes at the bottom? They don’t seem to be draining..

That might have been an optical illusion. Something produced by the lights, because there were six glowing devices spaced around the underwater perimeter of the oval. Their lumens were some part of what gave the water that deep shade, and just about all of what allowed her to see the room at all. There was a touch of oddly-separate white around the rim of each, just enough to tell that it was there — but the rest was a different hue, and that was what reached the surface. Produced the faint glow.

Her first impression had been that the water was shining with darkness. It would have perhaps been more fair to say that the water was glowing with a particularly deep blue, just a few thin shades of chroma away from black.

Celestia brought her gaze up. Looked around the room. There seemed to be a theme,

“This is a lot of tile.”

“I wished for the ambiance to be proper.”

“…that black pattern on the back wall? With the thin white —“

Proudly, “— meteors streaking by.”

Celestia looked up.

“And the big round objects overhead? I can’t quite make those out.”

Very slightly abashed, “They started as asteroids. But then they turned out rounder than I had intended. With flatter bottoms.”

“Oh.”

“I was considering whether to paint them deep green.”

“Oh?”

“Lily pads.”

“Oh…”

Of the two, Luna was the artist. Celestia could, with some effort, usually manage to appreciate art.

“And the owners just let you do all this?”

Calmly, “I made a reasonable request.”

Because it can’t possibly be abuse of authority if you think they might muster the strength to say no…
Trust her.

“They also gain the results,” Luna added. “Which may assist their income. Tia…”

She hesitated, and the elder listened. Waited.

“…this is where I require your assistance.”

“What do I need to do?”

“Heat the water,” the younger replied. “More finely than the embedded wonders would allow. But — simply to the point where it exactly matches your body temperature. No more. And then maintain that.”

She didn’t understand the need. But that was hardly a prerequisite for love.

Something invisible rose from white fur. The pool warmed.

Luna nodded, began to lower a dark body onto tile. Celestia started to match the drop —

“Immerse yourself,” Luna said. “Slowly and fully. To the deepest part. You have enough room to move.”

The elder looked down at the younger. (With Luna resting now on the rim, farther down.). White wings twitched.

“Luna —”

“— I see your feathers shifting, sister.” It was almost a smile. “Your pegasus aspect dislikes this, for fully-soaked wings may negate flight. Silence it for a time. I require you to do this. No others.” The left foreleg gestured. “There is a ramp with hoof divots. Use it. Carefully. And once you are within… move as you wish, or remain still. But do not emerge. Not until the gift functions. Or… does not.”

The elder measured her next words.

“How will I know?”

The “I cannot say,” felt somewhat sad, and dark eyes half-closed. “I have hardly tested this with others. It is fully safe, Tia. Magic used only to arrange the conditions: nothing more. But as for the results… only you can determine that. Within. Please.”

The elder carefully trotted around the rim. (It took new palace employees some time before they were comfortable with hooves moving across marble. Tile was worse.) Found the ramp, and slowly made her way down into darkness.

Darkness mostly felt like wet fur.
And feathers.
Wet wings weren’t good —
put it away
— it was still strange, after so much time. How getting wet never really worked unless the whole body was in on it. A single dry square hoofwidth, and every other portion could feel like misery…

“Maintain the temperature,” Luna instructed as water lapped over Celestia’s spine, rippled the fur. “But now — allow yourself to feel it.”

The next word echoed oddly within tile, bounced off darkness and what probably wasn’t going to wind up as lily pads. “Sorry?”

She looked across to Luna. (Submerged like this, with her sister lying down, it was across.)

“You register the presence of heat as well as I do cold,” the younger dryly said. “To wit: deliberately. Allow yourself to notice warmth, Tia. I feel this is necessary.”

It took a small effort. Shutting a portion of her own magic down…

“…why?”

“More specific, please,” was now the driest thing in the room.

“This is body temperature. That’s almost tepid —“

“— and you are surrounded by it,” Luna cut in. “Move. Remain still, as it suits you. Wait.”

For lack of anything better to do, Celestia began to pace. Something which was slightly harder: even with earth pony strength at work, the water still created resistance.

One lap. Two.

“The owners keep this?”

“Yes.” Paused. “Although not at the current depth. The floor can be raised. I needed to accommodate your form.”

Celestia patiently waited for a size joke.
Kept waiting.
Three laps. Four —

— the water was there. It was very much there. From the neck down, she was saturated with it. It was there, and yet…

“— this is…”

Luna’s ears went straight up.

“Yes?”

“The resistance is — fading,” Celestia softly said. “It’s like I’m sliding through more than pushing. Like it’s just — denser air. And the heat is…”

“Go on,” the younger carefully encouraged. “Speak, sister. Whatever words appear within your mind.”

“…it’s nowhere,” the elder told her. “And it’s everywhere. The same temperature as my body.”

“The same,” Luna quietly added, “as the womb.”

“It’s — like the borders are fuzzing out. Between my fur and the pool…”

Luna slowly nodded.

“And my skin is tingling. Is that the minerals?”

“If you believe it is.”

More pacing, only with a slightly increased bend at all four knees. The surface rippled as the white back sunk lower.

“It isn’t even trotting any more. It’s… drifting…”

“The next part, then,” Luna decided. Her horn briefly ignited—

— the pool began to bubble.

Jets of bubbles were entering the water. Some came in from well-concealed nozzles on the sides, while others erupted from between the tiles of the floor. The liquid roiled, and darkness glowed across what were now shifting tides. No waves, only the churning of what was almost becoming white water — but merely at the very peaks of the shifting surface, added to brighter light around the bubbles themselves. Picking up the radiance from the rims.

It should have been startling, to have had the pool turn into a pocket of rapids without true current or rocks to break up the rush. It was not.

“…how?” Celestia softly asked, watching the specks of white glow speed by, with others breaking up against the large body. “How did you arrange —“

“The technique exists, sister,” was almost a whisper. “You know of it, I am sure. Pegasus magic. Compress the volume of air. It was simply stored. And now it is being released. I — tried to make the placement somewhat random. Almost self-defeating, to do so with purpose… but it seemed important…”

“It’s like the air jets from the floor are nearly solid,” the moving mare whispered. (And now the surface was truly churning, with darkness and light and perpetual movement.) “If I stepped on them, they might support me…”

Silence from the younger. Something forever rare.

The white body shifted. The mare giggled.

Light played off the tile. Light, and the lack thereof. Dancing together.

“It didn’t,” she softly declared. “But they tried. And… my body is still tingling. Everywhere the water is. The bubbles are hitting me, except they aren’t. It’s more like a — mobile caress…” And the whisper was saturated with wonder. “Luna, what is this? What are you doing?”

“Nothing,” was just barely audible. “I watch, Tia. That is nearly all. Watch, and — offer one more instruction. Take a breath. Hold it. And lower your head. Eyes as close to the surface as possible.”

The pool churned. Air pushed through water, met what was now a stilling body, and light scattered.

“Lower my…” The last decibels she had to give.

“Which means holding your breath,” Luna semi-repeated. “It was the last thought I had. The only process I could conceive to even try. Please…”

The white rib cage swelled. Knees and neck bent. Her head went down —

— the air jets stopped, the last bubbles rose and rushed past purple eyes—

— darkness
immersed in shadow
surrounded
and the darkness has weight, but just enough to tell you it’s there
your own weight, your own heat
buoyed
comforted
everything moving around me, everything all the time
(an instant, only an instant, can only stay like this for a moment)
and the rushing little lights go by, with flowing umbra surrounding them and the tiny white glints
the light which tells the darkness what it is, because you need both
they define each other
the flow moves, calms, continues on
(don’t let it fade)
(i have to come up)
and the light moving past and through me
the last creations of a different chaos
those are stars…

She stumbled out of the pool. Almost reeled, and perhaps some tiny part of that was due to the mineral content. The rest was something else, and it sent Luna back into a standing position within a second: something which only held until hooves frantically pushed towards the elder. Ready to prop the larger form up.

It put the younger in a convenient position. And her patience had to be credited, as well as her willingness to suffer a little discomfort. Being nuzzled by wet fur wasn’t exactly fun, and given their respective positions… there was a lot of dripping.

They nuzzled. At one point, Celestia found herself giggling. She also seemed to be crying, and the two states felt very much like the same thing.

The siblings nuzzled in the shadows: something which, if for but a moment, had welcomed them both.

They were very different mares. They always would be. And there was no true means to escape from one’s own perspective, not forever. To do so permanently would be to lose the self.

But for an instant, a moment, and whenever she came back to the intangible memory of gift and lesson… the elder was that much closer to understanding the younger.

Truly.