Kaelynn was... somewhere. Nowhere she wanted to be, nowhere she ever planned to visit. But it wasn't like she'd been given a choice.
She spent an eternity of bumping and jostling around, with the voices of other creatures practically right outside. How many of those others might be able to rescue her, if only they had any idea what was happening? Could she somehow sing them a message?
She tried a few tunes, but nothing was louder than the sound of jostling around her.
At least her kidnapper had packed her jar into plenty of dense padding, so she wouldn't be knocked around, or shattered to suffocate in the air.
I should've memorized those songs. The one she'd used to get her legs wasn't that complicated, really. She had tried to memorize it, in her (thus far) failed attempt to reverse her transformation and get back into the water.
But apparently I didn't need to learn that either, because some unicorn can just change me whenever she wants.
She could probably stew with her resentment for another several hours, and maybe she did. There was no frame of reference to the outside world, no way to know how much time was passing. There was only a smooth glass surface, bumping up and down in a way that made her feel gradually sicker the longer she felt it.
Until the bumping stopped. She watched, swimming near the top of the jar to see what might be happening. Then light cracked in through the ceiling, and the whole jar glowed with so much green light around the edges that she could see nothing of the outside world.
She did feel the world moving, listing violently to one side. Then she heard a voice, muted by the glass. Only its terrible volume was enough for her to hear and understand it at all.
"I hope you will find a home here," it said. "I know you may resent me now, but understand that I do this for your own good. I cannot allow something rare and beautiful to die out. I must preserve you, for the sake of the others like you who are not yet born."
"You don't have what you think you do!" she shouted, as loudly as she possibly could. But speaking underwater was a different kind of sound, and she wasn’t even sure it would be audible from outside the jar. Either it wasn't, or the pony wasn't listening.
Through to the other side, she caught a brief glimpse of that old face, holding her over something vast—like a whole ocean, trapped in a room with white walls. Much bigger than a tank for hobby fish—this thing was more like an industrial aquarium. Something that could hold her real self. Though the distance was so incredible...
Suddenly she tilted forward. She kicked her tail, swimming as quickly back the other way as she possibly could.
Nowhere near fast enough, not when all the water in the jar went with her. She slipped out over the edge, then she was falling.
Kaelynn screamed in naked terror—literally. Probably she pissed herself too, as she tumbled apparent hundreds of feet down through the air. Her tail and fins kicked in vain, unable to slow her.
Yet it wasn't falling as she expected. She seemed to be growing towards the water, rather than falling through the air. Her vision distorted and blurred for a moment, then suddenly she could see the whole room more clearly—just in time to drop headfirst into the water.
The cold of it was another shock, stunning her enough that she started shivering. But it wasn't just that. The water burned as it went down her throat, making her whole body twitch and spasm. Could she not even breathe it?
For a few seconds she drifted, hacking and struggling to breathe. She swam upward in the water by reflex, brushing up against the surface. Had she somehow changed back without realizing it? She tried lifting her head above the surface, taking in a mouthful of air—but that did even less, searing as it went down.
She exhaled, and began drifting down to the bottom of the tank. She saw an opening here, a tunnel or maybe a door leading into the rock. Pain passed through her whole body, from her head all the way to her tail. It didn't feel like drowning exactly, though she still screamed madly into the water.
Then it ended. She looked up from a layer of gravel at the bottom, and realized that she wasn't in pain anymore. She blinked, looking around the tank. Why had that hurt so badly... something about the magic forcing her, or maybe being small?
She looked up, taking in her surroundings. The room was roughly square, with stone on five sides, and thick glass on the front. Though it was a room swallowed entirely by stone, with several large drains on the floor directly in front of the glass.
Kaelynn instantly turned for the ceiling, swimming up as quickly as she could. She smacked her head into it after a few seconds, grunting in pain. More metal grate, this one positioned with barely any clearance at all. Probably her kidnapper had smacked it closed while she was suffocating.
"At the front of the enclosure, you'll find a crystal embedded in the glass. It will allow you to speak."
The voice came from the glass, apparently emanating from the crystal itself. But something else caught her eye, on the opposite wall. The corridor she had seen, leading backward into a dark space. Was there motion in the water beyond, the smell of someone else?
She turned away from that opening, making her way over to the crystal. It was a length of some semi-precious stone, carved with lots of little markings. But she didn't need to know how it worked to know she was dealing with a prison PA.
"I felt like I was going to die when I landed," she said. Her voice was far weaker than it had been, barely stable. "Were you trying to torture me?" The cold wasn't exactly pleasant, compared to the relative warmth aboard the Bright Hawk. But it wasn't going to hurt her—it was just a little uncomfortable.
"No." The old mare sat just beside the glass, watching her through her spectacles. "You made the transition from fresh water to salt water. Notice your body has become longer, smoother. You've lost the spots. I wonder if they'd be in the same pattern if we transitioned you back... but that's an experiment for another day."
Now that Kaelynn thought about it, she had endured this pain before. It had been so brief while she was at Mt. Aris, and more importantly she had wanted to change. Now she faced it naked and unprepared.
The pony rose, tapping one hoof gently against the glass. "I'm an old mare, so I will keep this brief. There are two ways out of this tank. One is steel, rated to resist a determined earth pony for many hours. The other is glass, the window between us. I know you could find a way to break it. Before you do, I wish to draw your attention to the drains."
She pointed with one hoof. "The entire tank behind you is higher than this drain. Once that glass breaks, it will drain within thirty seconds, killing you before you can complete any transformation song."
Even if I could make it work. She circled around furiously, taking in the tank. Aside for its single opening, there was a large light overhead—a skylight. The glass looked polarized somehow, so no one would be getting a glimpse of them from above. That explained the darkness of the water, it was still night out there.
But through the glass, a pair of electric lights kept that room at a steady brightness. There wasn't much through there—aside from the huge drains, there were a few benches and bookshelves, a desk, and a heavy jail-looking door.
Finally she rested her foreleg on the communication crystal again. "My friends will give you hell for this," she said. "One of them is a changeling. He probably watched the whole kidnapping."
The old mare actually smiled. "If you think the princess is going to help you, you're mistaken. Princess Twilight is far too invested in the transition of power to monitor such little matters as passenger manifests."
"Not her." Kaelynn leaned up close to the glass, baring her teeth. They were flat, unfortunately. She couldn't muster Galena's intimidating beak. "The others with me on that ship aren't from your world, bitch. We're aliens from a world a whole lot less friendly than this one. When they find out who took me, they're not going to ask for help. They'll get me out, no matter the blood it takes to get here.
"We killed a ship full of pirates, asshole. Don't think they won't kill you.”
Maybe it was just the glass, but this time Kaelynn could detect something different in the mare's face. But it didn't last long. "If that's true, you probably shouldn't have told me. I'll increase security until such time as it's clear your changeling bluff doesn't manifest."
She took another step back, and suddenly her voice became deeply muffled. "We'll speak again after I rest. Do let me know if there's anything I could do to improve the accommodations."
Then she turned, waking calmly away into the room. Kaelynn screamed into the water after her, letting loose with every profanity she knew—but it did no good. The old mare didn't so much as slow down. She reached the door, then Kaelynn got a single glimpse outside.
Narrow stone hallway, with bulky pony figures visible beyond. They slammed the door shut, and she imagined she could see several heavy locks closing over one by one, until the door was entirely sealed.
For a few seconds she just floated there in the water, all the energy of rebellion spent for the moment. She wanted someone to rage at, but there was nobody here but her own reflection, visible if she angled herself just so in the water.
Her kidnapper was right—her body was a little longer now, and the many dark spots on her underbelly and tail were gone. The change from fresh water to salt water. But why bother keeping a tank of salt water, when they were living in a city that could probably give her an unlimited supply of fresh?
Why go to all this trouble to kidnap her? Whoever this person was, she'd been able to locate her within a single day of her arrival in Canterlot. Apparently seaponies were that rare and special.
She drifted down towards the bottom, and felt the slight discomfort as her tail brushed against the rocks there. A gentle current seemed to pull down all the time—probably a filter system that she couldn't see.
If she hadn't been dragged here against her will, it might've been decent accommodations. Far better than the foot of water she could keep in the captain's quarters, constantly sloshing around, making the ship difficult to balance, barely enough to move, fouling up in some parts and needing her to swim through to circulate it manually...
This tank was clear, and there was enough water here that she probably wouldn't be able to ruin it faster than it was cleaned and refreshed.
Something moved in the dark water, quiet enough that she might've missed it. But there was a smell that came with it, one that she'd never noticed in anything before.
Something reflected in the electric lights from outside the room, a pair of somethings. As if on cue, the lights went out, plunging her into near-total darkness.
There was only moonlight around her now, streaming through a single central shaft. It was bright enough to show her own scales, which reflected almost metallically in the light.
She felt the water move around her, and this time she was positive she hadn't been swimming.
"Hey!" she called, lifting vertically in the water. Her own fins distorted the current, making it harder to sense whatever she had felt. But she wasn't going to let something mysterious come and attack her without fighting back. "Show yourself! If there are monsters in here to eat me, you should know I studied karate in elementary school!"
It was one of the stupidest things she'd ever said—but she also wasn't a terribly good liar.
Apparently her conviction was enough, because something moved in the water not far away from her. Her eyes caught only its faintest outline—but there was a long tail, and a lithe body, not all that different from her own.
Then a voice, singing in an octave lower than hers. But despite being male, he sounded far less confident. Actually, he seemed terrified. "Sorry! I... I hope I didn't disturb you."