Kaelynn was making progress.
Every morning she told herself that—or at least, she assumed they were mornings. Her prison had no windows, nothing more than the magical glow of crystals they could brighten or dim on command. But she could keep track of the days in other ways. The demands of Morningtide made that easy enough.
Most of the time, she just wanted to show her off. Groups of well-dressed ponies visited their tank. They weren't what she imagined when she pictured a group of people willing to look at a kidnapped person locked in a tank, either. Not bulbus and sweaty, covered in gold chains. These were dignified ponies, wearing fine gowns and sharp suits.
Most of them didn't even know she was being held against her will, not after that first group. Morningtide had made it quite clear what she wasn't allowed to talk about on the very next day.
"You will neither state nor insinuate that you are not being well-treated here," Morningtide had said. "The instant you do, my patience will expire." She lifted something into the air—a bottle, with faintly luminous contents. "Know the position you're in, Kaelynn. This potion, added to your tank, will ensure that repopulation efforts begin promptly." She settled it back down, tucking it away behind a stack of books. "I have no desire to escalate to such barbaric measures. Do not force my hoof."
Kaelynn nodded once. She could've raged against her, bashing up against the tank, screamed wild profanities—or she could keep her mouth closed, and wait for an opening. The latter was an easy choice. My friends are coming for me. When they do, you better hope I'm feeling forgiving. "Is there anything else I shouldn't tell them?"
The unicorn waved a dismissive hoof. "This talk into... other worlds that so fascinates you. That theory is known to most ponies who study your species. All reputable scholars have dismissed it. It really would be better if you kept that to yourself."
Kaelynn circled the little fishbowl once in agitation, stirring the water beneath her. As she did, she caught a scent from the tunnel entrance. A pair of eyes watched there, just out of sight. But what else was there for Tellin to do? "You're asking a lot, Morningtide. Do your visitors want the truth, or entertainment?"
"Entertainment." She didn't even hesitate. "You already met with the genuine naturalists. They know as I know that you don't come from an existing colony of seaponies, and so their curiosity waned. Consider this position... elevation. By saving this species, your life will have greater purpose than it ever could have. One day, your descendants will be released into one of Equestria's sheltered lakes to rebuild. Seaponies through all history will have you to thank for their survival."
She curled her tail upward, covering herself subconsciously. Funny how she could come so far in overcoming human taboos since arriving here—but nothing could bring them back faster than being treated like an animal.
Morningtide seemed to sense her hesitation, because she held something up in the air ahead of her. "Don't think I can't be reasoned with, Kaelynn. Cooperation brings great rewards. Look." She held up a single flat page, then dropped it into the metal chute atop the tank. Kaelynn caught it by reflex, balancing it in one hoof.
"For the Nurturing of Useful Plants"
It was a sheet from the hippogriff songbook, drawn on that same waterproof material. It had been sliced away from the binding, but still looked like the original to her. No reason to lie, just give me a song I can't use.
"We would like to see your songs in action," Morningtide went on. "Various magical experts will be in the next group. You should rehearse that before they arrive."
Kaelynn skimmed it, then looked back. "I think I'll need something to grow. And probably Tellin's help. We've had more luck singing together than apart."
"Not unexpected. Speak to him, I'm sure he'll cooperate. I will reward you with more of your collection. Once I've determined the songs are safe, that is."
Maybe this was what Kaelynn was waiting for. Not even the hippogriffs had known what those songs did. Most titles could be interpreted in many different ways—maybe the correct one wouldn't warn Morningtide of the weapon it would be. Or maybe I don't need the songbook at all. There was no song for making tools, not exactly. She'd just wanted to do it, then she had.
Unfortunately for Kaelynn, she hadn't yet been able to reproduce that particular experiment.
That wasn't to say she was wasting her time. Morningtide only visited for a few minutes each day. When she wasn't around, Kaelynn worked. She tried to start with the piano, but had met unexpected resistance from Tellin.
"We can't take an instrument apart!" he had argued, shoving her away from the case with more force than he'd yet touched her. "Morningtide had a pony play it for me—it's beautiful!"
"Out there it is," she said, swimming along to the keys. She pushed a few of them down at random with a hoof. Only one actually played a note, not even resembling the C she'd intended. Not to mention it was so muted it was barely even audible. "Does that sound like beautiful music?"
"Break something else," he argued, determined.
No matter how much she wanted to keep fighting with him, Kaelynn knew it was a battle that couldn't be won. Not because Tellin had ever done anything untoward, or that he'd use his greater size against her. But all he had to do was say one word about what she was doing to Morningtide, and all her preparations would be for nothing.
"Okay. I'll clean up something else." She swam off, and had to make herself content with other ruins. There was plenty to keep her hooves busy—half of what filled the bottom of the tank looked like musical instruments of one sort or another. Most had fared even worse, and barely even suggested their original purpose.
Kaelynn used her tools to make more. She made prybars, wedges, a pair of heavy snips. She made a spear, though Neptune only knew if she would need it. One thing was certain; she wasn't going to attempt her escape unarmed.
Respecting Tellin's precious relics didn't mean she was entirely free of his attention. Most of the time it was simple curiosity. But not always.
"Kaelynn," he hummed, late into the evening another day later. At least, she thought it was night. She couldn't know for sure. "Has Morningtide talked to you about... why she does all this? Why she made us this shelter?"
Kaelynn shook her head. "Any reason she gives is self-serving, Tellin. We're increasing her reputation, her... family's prestige. Every day she brings in another group is another day that ponies get to ogle and clap at how generous she is."
His melody transformed, the beats becoming harsh staccato notes. "Morningtide wants Seaponies to survive," he went on. "We're the last of our kind in the whole world. Morningtide gave us a place to hide, where we could make more creatures like us. Don't you care if we die out? Do you wanna be the last seaponies to ever swim?"
Kaelynn tensed. It would be so easy to come up with a lie. But the music didn't work that way—any emotion she wasn't feeling would sound like a parade of wrong notes. "I care, Tellin." She set down her spear, and its half-finished point. "Maybe that's really what we'll have to do, one day." She rested one hoof on his shoulder. "But not while I'm a prisoner. If we did what she wanted here, we'd bring people into a world of... walls, and cages. The Storm King is dead, Tellin. The ocean is safe. If we were out of here, we could live anywhere we wanted."
He retreated from her, backing away through the water. "You keep saying things about Morningtide, Kaelynn... Are you even paying attention? She protected me from the Storm King, she gives us everything we ask for... why would you even want to leave? Even if the ocean was safe, you wouldn't want to live there! Ponies have a city. What's free even mean, if we have to hunt our own fish and live under a rock?"
He would probably be crying, if they weren't underwater. Oh god. This is so much worse than I thought. You think Morningtide is your mom. Did Kaelynn even have enough time to win him over? "I don't want to upset you, Tellin," she said lamely. "I'm glad Morningtide has taken such good care of you over the years. But can you see that she hasn't taken good care of me? I was happy outside, and she forced me here. She's holding me here against my will."
Tellin didn't even stick around in the water after that. He swam quickly away, vanishing into the gloom in the back of the tank without another word.
Sorry kid. Kaelynn went back to work on her spear, filing away at the blade. She had better hurry if she expected to get out of this tank. It was no wonder that Morningtide was so confident trapping her—she'd turned her fellow prisoner into another jailer.
They slept on separate sides of the tank, so it was nothing strange that Kaelynn didn't see him again until the next morning. He delivered a pine box to the table in front of her, with four little plants packed in gravel inside. Underwater ones by the look of it, with leaves browning on the edges from too long out on the surface.
"Morningtide brought these," he said flatly. "I think we're supposed to practice? Ponies coming over later want to see our songs." He didn't meet her eyes as he settled something down onto the table beside them: the songbook page Morningtide had given her the other day.
She looked from the page to Tellin, then back again. Just as she couldn't lie with her song, his emotionless neutrality sounded hollow to her ears. There was pain under there, poorly concealed.
Kaelynn set down her tools. "I can handle it alone, if you don't want to sing with me," she said. "I can perform for Morningtide and her guests."
"No," he said, a little too quickly. "I mean... I'd still sing with you. I think you're wrong about a lot, Kaelynn. But we're stuck together, so... I'll just have to hope you change your mind."
She smiled weakly back at him. "Alright. Let's try and grow some plants together."
Easier said than done. Their argument the night before meant the two of them were discordant now. Singing a magical song together required a level of cooperation from both parties, one that Kaelynn could hardly feel at first. Until she could, the plants didn't change.
Not only that, but this song specified a "Confident Knowledge of Hunger" required in order to perform the song properly, and the two of them were just too well-fed. At least until they'd been practicing for a few hours, and the time between meals began to stretch. That was the first hint of harmony between the two of them.
They sang of gardens and growing things, of what it was like to swim through a forest of seaweed and beneath bright green lily pads. It was a song only Kaelynn could lead with any authenticity, since she had actually been to places like that. Her diving experience formed the foundation of a song.
She hardly noticed the change, until creeping roots tumbled over the side of the table, and the great central stalk of a length of seaweed began to cover up the sheet music.
"I... think that's enough," she finally said, trailing off abruptly. As it turned out, only two of the plants had grown. Two remained in their pots, unchanged.
"I can't wait until we have the whole songbook," Tellin said. He tore off a large flat leaf of seaweed, then bit into it. He hummed happily at the taste, grinning. "It's so fresh!"