Sonata peeked back at the little clown fish floating dazedly in the wash of her tail, almost brought a hoof to her mouth, but stopped when Adagio rapped one on her head.

“Just focus on the ceremony,” she hissed.

“I will! But that fish was so cute, and it barely took a song to have him following me.”

“Fish are food, dolt. Not pets. You want a pet, I’ll ask mom to get you an eel. After tonight.”

But eels bite, Sonata wanted to say. Not that Adagio would listen to her. She never did, except when Sonata messed up or made a mistake.

So she held back and focused on the swim up the cliff face, careful to stay close to the wall so the deeper ocean currents couldn’t pluck them away and delay them any longer. Not that Adagio seemed to care about delays, even with the sun-pearl glowing between two chorus pearls.

Sonata sighed, flipped her tail and raced ahead of Adagio, then swept up in a burst of speed and drifted to a halt. Below her, in a shallow valley covered by a warm sea off the coast of the Equestria Luna and Celestia were trying to build, lay Seastar, the largest city of the seaponies in all the world.

From far above the cliff’s edge, she could see the pathways of smooth, white sand made their way between shelters of sunken ships and natural caves, linking the city together with a net of gleaming silver that was far easier to glide over than the rough rock and coral forests that pervaded elsewhere.

Many of those lights had been enchanted by Adagio, and she never stopped nattering on how hers shone more brightly and with a color truer to the sun than any other. Those few that Sonata had sang glimmered here and there in wild colors rarely seen below the sea: rosy red, twilight purple, and sunset orange were a few of them, but only seaponies with a desire to highlight odd wares from the surface world bought them.

And, as the sun set, all of the pinpricks of light flared brighter and spread their radiance farther so that the city shone like she imagined the stars must in the air above at night. She wished, then, to be able to look down upon her ocean home and see it as it must appear to the myriad of ships that regularly plied the waters far above and sent ponies in rafts to trade with those seaponies accustomed to their odd ways.

But she knew it wasn’t ever to be, and her gills ached at the thought of suffering the air above more than she had to for the Singing of the sun into a pearl. Even if her pearls weren’t used as more than interior lighting, it was a special thing to feel the dry air in her lungs instead of gill-filtered water.

Ahead of them, the glow resolved into six solid beams of golden light slowly fading into the magenta and purples so rarely seen in the deeps, and none richer than the pillars at morning and dusk.

The Pillars of Oceana, so named for their discoverer centuries upon centuries ago, were six massive, crystalline columns that struck upwards from the seabed and pierced the sea above during low tide and shone with the brilliance of the sun when it was high above, but brighter still with the moonlight. The elder insisted it was because of the sea’s affinity with the moon that that such occurred on nights of the fullest moon, the magic they poured forth was special.

Even then, so early in the night, Sonata could feel the magic humming through the water, tingling her scales and settling in her mane like an electric current from one of her mother’s waking songs.

Ahead of them, a large cluster of seaponies were clustered around one of the pillars, including the chief, recognizable in her driftwood and coral headpiece. The light flickered rhythmically in that pillar, dimmer than all the rest, and as she focused her attention on it, she could make out the sickly feel of it from afar.

It made her shiver, despite the warmth of the ocean. “What’s going on?”

“I don’t know.”.

Sonata whirled to find her sister floating behind her. She hadn’t even felt the wake on her crest.

“What I do know is that you’re going to make us late if you daydream up here.”

“Why?”

“Gah! You’re insufferable. How can you remember a song after the first hearing, but forget the why of everything else!” Adagio rolled her eyes and butted her head against Sonata’s back. “I have been chosen to portray Oceana, and if you make me late, you. Will. Regret. It.”

With each word, Adagio butted once more.

“Fine! I’ll go. You don’t have to be so pushy.”

---

Sonata drifted in among the crowd of ponies examining the pillar, listening to the murmurs and trying not to let the feeling of its magic get to her. The pulse was rhythmic, yes, but there was a tonal disharmony underlying it that made her mane want to stand on end.

“…started yesterday…”

“…full moon didn’t come on time. We need to…”

“…calm down, everypony.” That was the elder Tidal Draft, the advisor to the council on matters of historical significance. “The resonance is normal. If you will recall, one decade ago, Rising Tide’s pillar did this same thing, and before that, Swift Current’s, nearly two centuries ago.”

“But this is Oceana’s own pillar!” somepony else cried out from the edge of the crowd.

“Yes. But I this is a part of the cycle. I have read it in the oldest histories, and the pattern has remained ever the same. Remember, the pillars have always been here, since before Seastar was founded, and forever they shall remain.”

That seemed to satisfy most of them, and the crowd began to disperse like a lazy school of fish breaking around a ship’s hull.

The chief and Sonata’s mother remained behind, conversing in low tones.

Sonata hung back, watching, trying to listen in without being obvious by pretending to study the pattern of fading light shimmering across the sandy path. Then a meandering thread chased by a shadow drifted along the bottom, and she got lost in following it in a slow, lazy circle. A couple times, she glanced up when the glimmer and shadow disappeared, but the talk appeared to have meandered from the pillar to other things, and the Elder was laughing at something her mother had said.

Her mother, Sea Sharp, was renowned as the best Singer in the city, and a beauty besides, traits she often boasted had been passed on to all three of her daughters, but Sonata thought she had more of her father in her. From what little she could remember of him, Rolling Tide had been a dreamer like her, and a talented pathfinder in the deeps, where light meant less than nothing, and was often a liability.

Her talent went more towards the songs her sisters so diligently studied and memorized, but she often fancied that she would go off on adventures like her father, exploring the deep places and bringing back treasures from ships that had sunk far from the reach of Seastar’s foraging parties.

One day, she decided, she would find something that would make her father proud.

Maybe she would find him, lost somewhere in the deeps. Maybe he would even still be alive.

She could dream.

---

Hours later, as the moon was rising into position and the pulsing column subsided, Sonata drifted above the crowd with her mother and sister, Aria. Below, everypony else was lounging on kelp cushions and feasting on other delicacies being passed around by drifting vendors. Adagio was singing on the raised coralwood platform, her voice pitch-perfect as usual, but it was slightly off from what Sonata remembered last year.

It was subtle, just a minor pitch shift, but it was consistent, and the pillars responded as they always did, igniting into a blaze of silver fire at key verses dedicated to the pony each pillar was named for. The crowd, as usual, ate it up and sang along in a hundred-part harmony that did nothing more than annoy Adagio.

She could tell, even from a distance from the way Adagio’s tail flipped just a little too hard to get to the next position, and the way her higher notes reached just a little above normal.

And then Adagio stopped swimming and stopped singing. She was in front of Oceana’s pillar, and the silver fire that coursed down the length of it from the surface faltered, grew brighter, and winked out.

Shouts rose from the crowd, curses and imprecations at Adagio, fearful shouts pleading with Oceana for guidance, and one peal of laughter from Aria Blaze, their sister, quickly shushed by Sea Sharp.

“Your sister has been preparing for this for months, Aria. Show a little respect.”

“I wouldn’t need to if she’d practiced. I still can’t believe they passed over me for the role. I’m ten times—”

“Shh.” Sea Sharp tapped Aria briefly on the hoof.

She started singing again after a long moment of staring at the pillar, her voice quavering at first, but growing stronger and stronger, overwhelming the crowd’s displeasure and filling the ocean with her voice. The column flared again, blazing silver streaked with gold, and steadied.

The rest of the ceremony went on as though nothing had happened, and the sensation of the magic flowing out from the columns of silver fire felt as sweet and calming as ever. The only disharmony came from the crowd, murmuring instead of singing along.

---

Sonata raced to catch up to Adagio, fighting both late night current and her sister’s wake. As soon as the ceremony was over and the Elder had come up to placate the crowd, she had fled.

Sea Sharp had sent Sonata and Aria after her, then swam towards the elder once more, concern etched plain in her features.

“Why did she stop singing?” Aria asked, The faintest tingle of the Singer’s art touching her words to be heard in the rush of water flowing over them.

“I dunno. I remember she was head-butting me to get me there in time for it, but I dunno why.”

“So she could show off, obviously. Did you hear how she butchered the harmony? And the way she fixed it… always more force than thought. I wouldn’t have faltered.” Aria laughed. “She’s probably broken the pillars.”

“No! She couldn’t have! I felt them… they didn’t feel broken. Even the magic felt the same.”

“Yeah, like you’d know.”

“I do!” But there had been that sickening feeling when Oceana’s had pulsed so oddly in the fading sunlight. “But maybe something else did.”

“Whatever.”

Aria said nothing else, and they sped along, just barely keeping Adagio in sight because of the sunpearl she wore as a part of her costume. One of mother’s, Sonata thought, recognizing the distinctive opalescent glimmer that only their mother had been able to achieve in the sun’s light.

Adagio led them to one of the farther kelp forests that was still in the domain of Seastar, and one of the least visited. Coralwood spotted with anemones grew everywhere, threatening the unwary or the unlucky with a painful sting, worse if one of the fragile trees crumbled.

The light winked out just before the edge of the forest.

“Where’d she go?” Sonata slowed, earning a glare and a tap from a hoof on her head.

“Where she always goes when things don’t go her way.”

Sonata opened her mouth to ask where, but Aria shook her head and pressed a hoof to her lips.

Silently, they slipped along the sea floor, wending through the rocks and short strands of kelp towards a giant boulder resting in a massive trough of sand, as though it had been dragged there by a giant hoof, or thrown.

But as she got closer, Sonata found that the current flowed away from the stone, not strongly, but enough that she could feel the pressure distinctly despite how quickly she was swimming. Around the base, there was a slit of rock worn smooth by age that Aria dove into without hesitation.

“Aria? Are you sure this is safe? What if…” But Aria was gone, leaving Sonata to drift, slowly swimming against the current. What if the cave collapses? Mom said that’s how dad was lost. Not dead, just… lost.

“Are you coming or not? Adagio is down here somewhere.”

“Yeah, but—”

“Just get in here before somepony sees us.”

Slowly, tapping her hooves together, looking at every surface and every crack for signs of stress or shaking, she swam on. The cave walls looked as smooth as glass, almost perfectly round, and filled with a soft blue radiance that clung to the every surface in a near uniform coat. Of course algae would be living here, she thought, raising her muzzle to taste the water more directly. It was rich with minerals the tangy taste of nutrients.

She reached out and almost touched a wall before drawing back and flipping her tail to catch up to Sonata. Some kinds of glowing algae were toxic, and they might be hiding more insidious things, like glowfish or anemones.

“Can’t believe you’re scared of caves.” Aria rolled her eyes and started down the long, smooth passage. “We live in a cave.”

“We live in our home,” Sonata corrected her, staring about and looking for any similarity. Where their home was squared and rounded in turns, this was all round, alien and unfamiliar. Her room, the roundest room in the series of caves hollowed out by Song and hoof, had all kinds of treasures she’d found. This place was barren of all but the uniform blue glow.

“Same thing. Cave, home. It’s a grotto, just like this one.”

“You’re sure?” She eyed the tunnel again, and almost saw a bit of home in the way an outcropping stuck out from the cave floor. She squinted. “Maybe…”

“Yeah. Now shut up so I can listen.”

They followed the sound of soft singing until the glimmer of gold began to gleam brighter than the pervasive blue. Adagio swam slow circles in a wide chamber where the current seemed to pause. Above, the gleam of argent moonlight filtered past slowly waving fronds of kelp. In the center of the chamber, a heap of stone clustered about: the crumbled ceiling.

Sonata swam to it as swiftly as she could, eyes glued to the ceiling until she was directly below the opening.

“Calm down, Sonata,” Adagio purred as she swam up. “The ceiling collapsed centuries ago.”

“How do you know? It could—”

“Because I know. I pay attention in class, dolt.” The lilt was gone from Adagio’s voice. “How you get by with daydreaming, I’ll never know. But it is good you’ve both found me.”

“What? Why?” Aria swam up beside Adagio, grimacing up at the ceiling for a moment, then drifting down to lounge on a smooth boulder. “Please tell me it’s not another one of your stupid schemes to find some ‘long lost’ treasure of the land ponies. I can go to Sonata for that kind of trash.”

“It’s not trash!” Sonata swatted Aria’s mane with her tail.

“No!” Adagio’s shout pulsed in the cave, reverberating. “I didn’t stop singing for no reason. The pillar, Oceana’s pillar, showed me a vision of—” She cut off, glancing at Sonata. “Of treasure beyond any of our wildest dreams, and power, Aria. Magic to stir the seas and make even the landborn quake with envy.”

“Yeah. No thanks.” Aria slashed a hoof through the water, rolled, and swam up to face Adagio muzzle to muzzle. “After your last scheme landed all of us in hot water with the Elder, I don’t feel like risking my tail for your pleasure.”

“This is different! I swear. Listen.”

She began to Sing. Not in the smooth, charismatic tones of her usual persuasions, but jarring, painful to listen to. But there was power in the not-quite words, and visions of treasures that Sonata could just barely glimpse, and could not identify through the haze of conflicting thoughts the song inspired in her. She had the feeling that they were all that Adagio had promised.

When Adagio finished, a glimmer of red shone in her eyes, so quickly faded that it seemed to have been a figment of the imagination.

“Did you see?”

“I heard a lot of noise,” Aria grumbled, “and I think I hallucinated because I’ve never heard you sing that badly before. Did you hit your head on the way in?”

“I saw,” Sonata whispered as her sisters glowered at each other. “I saw…” The images kept slipping away from her, never quite in focus enough to tell whether it was gold, silver, or gems that lay just beyond the reach of her awareness. “I don’t know.”

“Gah! You’re both hopeless. Have you never heard the tale of the Old King of the Sea?”

Sonata shrugged along with Aria.

“He was the ruler of of the oceans, from darkest depth to shallowest shore, and when he ruled, he commanded even the storms. It’s said that no pony could sail the seas without giving him tribute, and even then he could decide on a whim to sink a ship. To us, he was a god, and favored us above all else.”

“Oh! I know this one.” Sonata bit her lip for a moment. “It was part of a song the Elder sang last year. ‘And when the king went mad, Oceana, moonlight and fire clad, did trap the mad king and all of his wrong, and sealed him away with a song.’”

“Yes. Very good, Sonata.”

She beamed, swam around the pile of rubble and perched atop it to watch Aria and Adagio back down.

“She has the right of it, Aria. The pillars are not just magical crystal to protect our city, they’re jail bars for the king, and it is our yearly song that keeps the bars strong.”

Aria floated back, an expression of dawning realization widening her eyes as she tried to talk.

“Think of it! ‘The king and all of his wrong.’ The tributes! Think on it, Aria. We think of tributes for safe passage a wrong thing now. All of it.” Adagio swam up, then in a circle, hooves spread wide. “Centuries upon centuries of tributes from the surface world. Not just in gold, but in magic, too. Not simply sang magic, but the magic of the land ponies, too.”

Sonata giggled, rolled over on her perch, and peered up at the silver-limned fronds far above. She saw not kelp, but clouds, and stars, and all of the other wondrous things the land ponies took for granted. She saw, too, her father in his endless quest to better their family, to provide more than just the basics to all of them. She could do him proud if she brought back even a hint of what Adagio said was down—

“Wait. If the pillars are bars, where’s the cell?”

---

The Deeps. The darkest chasm in the whole of the known ocean, the deepest, most treacherous place in the whole of the world if the land ponies were to be believed.

Sonata hooked her hooves over the edge of the chasm, pulled herself forward with her flukes dragging in the mud, and stared into the depths. A few hundred hooves down, the walls of the chasm seemed to end in jagged shadows, like the mouth of the mythical megaladon, opening wide to swallow her whole. Just as it had swallowed her father, and eaten him so completely that nothing remained but his memory.

She swallowed.

“Are you sure we have to go down there?”

Adagio spat out the strap of her pack, stolen from the local garrison, and glared at her. “Yes. I told you a dozen times on the way here. Now come get your gear.”

“You’re welcome, by the way, Adagio,” Aria growled as she squirmed into her pack and settled the pouches about her belly, within easy bite or hoof reach.

“Yes, yes. Thank you.” Adagio rolled her eyes and held up the straps of Sonata’s pack between her hooves. “Now come on.” She shook the pack once more.

“I-I don’t want to. I know I said I did, but—”

“There’s no turning back now! The chance for that was gone as soon as you said yes the first time.” Adagio hooked the pack in one hoof and swam up to her. “Now get this on or we’ll drag you down without, and you can rely on your own song to light the way.”

“B-but songs don’t make light without—”

“I know that, fool.”

“Adagio,” Aria said sharply. “Let me.”

“Fine.”

Sonata cowered back from Adagio, glanced back along the sanded path to Seastar, some miles distant, and the dim glow of the pillars and the moon, far overhead.

“Haven’t you been excited, Sonata?” Aria asked. She took the pack from Adagio with a warning glance at the other and swam down to settle in the mud. “I know you dream of finding treasure. This one is just a little harder to find, that’s all.”

“But dad—” It hurt to think about it, and the yawning gash in the earth behind her felt like it was sucking at her, drawing her in, just as it must have for him.

“I know. But dad was not a strong Singer like us. Like you, eh? And the three of us together… do you remember when we sang down that giant squid last year? Everypony else wanted to hide until it passed, but the three of us charmed it away. It hasn’t been back since.”

“Yeah.”

“We can do this, Sonata.” Aria leaned in closer. “Prove Adagio wrong.”

Sonata thought about that for a moment, trying to remember anything else Adagio could be proven wrong about. “But then the treasure won’t be there.”

“Not about that,” Aria’s eyes twitched upwards briefly, and she grimaced. “Prove to her that you’re not a coward.”

She called me a coward? But she kept that thought to herself and only glanced at Adagio, eyes narrowing. “She didn’t want me to come along.”

“Yes, she did. She needs both of us, but she’s afraid you’ll be too scared to go. Dad’s death—”

“We don’t know that!” Sonata snapped.

“It’s been years, Sona.” Aria drew a hoof along her muzzle, pulled her into a tight embrace, and whispered. “I miss him to, you know. But you need to accept he’s gone.”

“I-I can’t. Not until…” Sonata looked down at the pack Aria held out to her, sighed, and struggled into it. Immediately, the gloom of the chasm began to fade, replaced instead by a soft silver glow where the walls should be, shaded in places, brighter in others. Beyond the edge of the glow, there was only a dim gray shadow, suggestions of shapes.

“Cool, huh? It’s mom’s latest enchantment. She calls it Moonlight Sight. I helped her with it. It’s sang into the buckle here.” Aria tapped a silver buckle that didn’t seem to be holding anything in place. “So, whatever you do, don’t lose it.”

“Yeah.” She touched it, briefly wondering why it was so new.

“I insisted,” Aria murmured, “after Dad got… lost that the explorers have something better than a directional light.”

Adagio swam back from farther down the edge of the chasm, staying clear of the lip just as they were. She slowed, eyes fixed on Sonata’s face, and nodded. “If he’s down there, we’ll find him, too.”

Sonata jerked the strap tight around her chest and waist, and swam out over the edge, feeling the pull of darkness and the depth sucking at more than just her body, but her soul, too. But that didn’t matter.

“Let’s go.”

She didn’t miss the brief nod Adagio gave to Aria.

But that didn’t matter, either.

---

Even beyond the silver shading of the Moonlight Sight, Sonata could feel the darkness tugging at her, beckoning, urging her to remove the buckle for just a moment and experience what it felt to be in a black so deep that everything beyond her eyes may as well not exist. She resisted the siren call and swam on beside her sisters.

Aria revealed that she had stolen a map along with the packs and they studied it from time to time, arguing over this and that feature glimpsed in passing far away down the chasm. There were many marks in a variety of colors—all washed out to shades of gray in the magical sight—marking dangers, rest camps, sunken ships, and even a few rare, ruined hovels in the style of the surface world.

Sonata puzzled over these, even swimming to within a few hundred hooves of one to inspect the odd architecture, stone and wood slumped in like a collapsed cave. That image alone convinced her that surface ponies were crazy.

Her detour did not please Adagio.

“Stay with us! The vision I received said little of dangers, save that there must be more than evident.”

“Common sense says that,” Aria said.

“Shut up,” Adagio hissed.

Aria opened her mouth to reply, but a swift hoof-wave silenced her.

A moment later, Sonata felt it, too. Something big was moving in the deep, beyond the limit of their sight, but its wake sent a wash of colder water up, along with a shiver of fear that froze her muscles and seized her throat.

They kept silent, huddled against an outcropping of rock. Some creatures of the deep did not need eyes to see their prey. To something that big, anything at all in the chasm would be its prey. The thought did nothing to ease Sonata’s heart as it hammered in her chest.

“We must be quiet from now on,” Adagio whispered in her quietest voice. “No noise.”

Sonata slipped a fin out into the chasm, testing. The chill in the water had subsided, and she nodded, then slipped out into the deep again, belly as close in to the cliff wall as she dared. Aria swept past her, farther out, and Adagio close behind.

Twice more, they hid or pressed themselves so close to the wall it was as though they became the stone, but the creature that had such a massive presence stayed outside of their sight. That worried Sonata more than if it had shown a fin the size of a building. Something that massive could not be real.

And yet it was. Adagio stopped them to mime at the map, tapped a symbol towards the bottom of the chasm marked with the universal sign for danger and circled several times, then pointed down. The look on her face was enough to tell Sonata she was feeling the same terror. Also present, however, was a firm set to her jaw.

No other notation was made below that symbol, there was no mark for the bottom, and nothing beyond a rough sketch done in simple lines instead of the detailed contours above. The knowledge of the garrison ended there, and if any else knew deeper or farther, Sonata could not think of them.

And yet Adagio tapped in that empty space, nodding firmly, jaw set, lips firm. Then she tapped a place just above the mark and gestured at each of them in turn.

Sonata swallowed. Less than the distance between home and Seastar lay between them and whatever stirred fitfully down below.

In gestures and looks, Adagio indicated that they should stay close to the wall, have a song ready, and gestured to Sonata, giving her a firm nod. Aria nodded, too.

Me? They want me to lead the song? Sonata swallowed, staring down into the gray abyss. They were asking her to lead them all down there.

“Why—” Sonata quailed at the sound of her own voice, loud in the long silence, and Adagio stuffed a hoof against her mouth, head shaking vehemently, eyes wide.

Below, rock clacked against rock sharply as the massive presence stirred. It had heard her, and in the dim, dark gray at the very limit of the Moonlight Sight’s sphere, a great curve bulged upward, spreading the full width of the Sight’s radius, smooth, enormous, undoubtedly deadly, then subsided again without them seeing more than that.

Sonata didn’t have to look to either side of her to know her sisters had seen it, too, as they were latched onto her as remoras to a shark.

She couldn’t count the heartbeats between when the creature made its appearance and when Aria and Adagio let their forelegs fall away to cling to the cliff face instead. She, too, tried to make herself bond with the rock, to hide away until the terror below disappeared.

Adagio shoved her forward, teeth bared in a grimace.

Gathering the tatters of her courage, and wrapping it in the hope that she would find her father, somehow, she started creeping down along the wall, placing her hooves carefully in the rock face and moving her tail not an inch.

Her normal approach to stealth was to appear as innocuous and harmless as possible, so there could be no possibility of threat in the mind of her target. But she had a feeling that this would be impossible, and downright deadly if she tried to do that with this creature. She had seen enough of Adagio’s and Aria sneaking up on unsuspecting prey, usually her, to know how to move silently and without a wake to give away her presence.

As they crept, the bulk began to fill the Sight’s limit again, growing ever larger and more distinct with every hoof placed and dragged. The very water around it seemed to pulse with an ever-so-slow beat with minutes between one and the next. Cold surrounded her, warded off only by the magic within one or another of the talismans studding the woven net of her pack.

There was space between it and the wall, though it seemed a paltry space, given the immensity of the creature, and if it shifted, it might squash them and never know they had been there. Or it might breathe them in through gill slits the width of a street and never know they were inside it.

Adagio saw it first, and tapped Sonata on the side of the neck, then pointed.

A small, dark circle on the creature’s side, as big around as she—dozens of them, running all along the length they could see. One blinked, then a dozen, then all of them, silver slits focused on them.

“Swim for your lives!” Adagio screamed. “Down! Down! Down!”

Silence shattered, Sonata pushed off from the cliff, flukes flaring wide, and dashed downward, her mind numb to all else but the dash. Obstacles, outcroppings of rock and debris, patches of anemone, shipwrecks older than any ever before seen, they all flashed by in moments, and she and her sisters wove between and around them while the massive creature woke.

She could feel it behind her, that massive wash of water pulling at her as it twisted. Rocks clattered, wood snapped, and it seemed as though the world shook with it's rage.

In a glimpse behind her, checking on her sisters, Sonata saw the creature’s maw, full of teeth larger than a ship’s mast, jutting over a jaw filled with row upon row of smaller teeth. At the end of its snout glowed a light so bright it seemed to her that it must be the sun in the sky above, brilliant and clear and golden even through the moonlight filter.

“Keep swimming, dolt! It’s trying to lure you in!”

It was then that Sonata remembered the song. No time for words, and it wouldn’t understand them anyway, she started to sing. Aria and Adagio picked up the tune moments later. It was a desperate song, swift as their flight down, the notes clawing at her ears, discordant and frightening even to her. The sound swelled, reverberated, adjusted to the acoustics of the chasm, singing with the echo, amplifying it. Into every long, ululating note, lingering beyond the point of rational thought, she poured her fear and desperation into the magic slowing the monster's advance.

They gained ground slowly, the song filling their thoughts as did the desperate flight deeper, and deeper, into darkness that not even the magical Sight could pierce.

The bottom swept up towards them, a darker black than that around them, irregular and soft. Small creatures darted away from them, pale eels, paler fish, and crabs of all shapes.

“There!” Aria cried, and darted left, hooves pointed at their salvation, a small cave open to the sea, some dozens of hooves above the bottom.

Sonata risked a brief glance up, halting her song.

Teeth filled the dark, and a brilliant, deadly sun that shed no warmth, promised only death.

She dove into the cave, Adagio just behind her.

---

The creature did not slam into the bottom, nor did it spend much time lingering outside the cave, though hundreds of eyes passed slowly in front of the entrance, peering inside, each one blinking. Once, the great lure illuminated the cave. Sonata felt its pull just as strongly, felt the fear that accompanied it, and resisted.

Then it was gone, and the cave shook with its passage.

“What was that?” Aria swam out of her hiding place behind a stalactite.

“The jailor, I suspect,” Adagio murmured. She was laying still between two stalagmites, peering at the map and using a rough bit of iron to mark out the bottom. “How far down do you think we swam past the creature?”

“The jailor?” Aria jabbed a hoof at the entrance. “That was no jailor, that was a nightmare out of tales so old—” She cut off, hoof flying to her mouth just before she vomited, shaking and drifting away.

Sonata was too tired to do more than flip her tail at the floating ooze.

“It was a jailor. The vision did mention something like that.”

“And you didn’t think to tell us?”

“Would you have come if I had?” Adagio looked up from her work, laughed, and turned back to it. “No, you would not have. You would have cowered and remained where you thought yourselves safe. You will thank me later.”

Sonata drifted towards the cave entrance, then darted away again as the light above winked on again. “We’re trapped,” she said.

“And you figured this out, how?” Aria said, lip curled in a sneer.

“It’s still out there, you can see it if—”

“Duh! And we’re going to be stuck here until we starve!” Aria rounded on Adagio. “And it’s all your fault!”

“We are not trapped,” Adagio said, calmer than she had any right to be. “Look at your… mess.”

It was drifting, slowly, but faster than could be accounted for in the still cave. Almost, Sonata would have said there was no current, but she lifted her head to the open water and smoothed back her mane, letting her whiskers drift free.

There was a current so weak she almost didn’t feel it, but she darted in the direction of the flow, around a rock shelf that only appeared to merge with the one behind it. Behind the paired shelves, another wall stood, pocked with holes and carved with what looked like seapony lettering, but not any she recognized.

“Adagio! Come look! Aria!”

They joined her, crowding into the small space.

“Look!” Adagio tapped a hoof against one of the holes, then another, a little farther down. The holes were not random, and as she tapped them, Sonata recognized them and what the lines of ancient script must have been.

“It’s music,” she whispered. Music so old she couldn’t even imagine how long ago it must have been put down, or how long ago it had been sang.

“Yes, and these here.” Adagio tapped the holes again in sequence. “Are the keys.”

“The vision tell you that, too?” Aria growled, squirming away from her sisters to lean against a corner.

“No, fool. The lettering does. These are the words to the song of unlocking!”

“What kind of idiot puts the keys to the jail cell in the jail cell?”

Adagio was shaking her head before Aria finished. “No, no. You’ve got it wrong. This is the entrance to the chamber where the cell is, not the cell itself. Anypony with the right skill can open this door. It just requires a harmony in three parts. Look. Three lines, three sets of holes.”

“How very convenient. Why three?”

“It’s a magical number, which you’d know if you’d paid any attention in class, Aria, and not daydreaming about being better than I.” Adagio shoved a hoof against her sister’s mouth, forestalling the argument. “That was poorly said, and I apologize, I’m sorry. Please. Let us open the door.”

Aria glared at Adagio a moment longer, closed her eyes, and nodded, though the grimace never left her muzzle.

“Sonata.”

“Yes?” She squirmed in to peer at the line Adagio was pointing at.

“This is your part. The notation here says ‘Sing for the tide.’” She tapped the one below it. “Aria, yours says—”

“I can read it! I do pay attention, you know. ‘Sing for the Moon.’”

“And mine says ‘Sing for the Sun.’”

Sonata stared at the trio of holes above her line, and brushed a hoof against the stone between them. In the silver light, she saw dust flake away over a line drawn sinuously between the three, like the rise and fall of a wave at high tide.

Her sisters followed suit, and found their three notes made circles—one small, for the moon, and a far larger one for the sun, the notes with greater dynamic range than Sonata’s simple sine.

Adagio started, her voice starting high, and Aria followed, hers low. Sonata waited half a beat, in between her sisters, and began with her note.

Three cycles, they repeated, voices rising and falling, crossing each other as the harmony built, echoing weirdly, as though the sound did not dissipate, but built in volume until it became a drone of sound painful to the ears.

In an instant, it was gone, the silence deafening, and the wall in front of them rose silently into the ceiling.

Beyond, a smooth, straight corridor went on for longer than Sonata could see. No plants, no mud, nothing but bare rock and a drifting bit of silt that never seemed to come to rest. The current was stronger, too, seeming to tug them along the corridor, urging them to wherever it led.

Adagio did not wait, and swam ahead, tail flashing, scales gold in the dim light.

Sonata stopped just before entering the tunnel and bent down to snag the silver buckle from its place in the netting across her chest. It came away easily, and the tunnel fell away into shadow, but not complete shadow. A glow permeated the water there, sourceless, as though every mote of silt shone with its own radiant glow.

“Aria?” Sonata asked, jerking her head at the flashing, golden flukes of their sister, almost beyond sight by then. She stuck the buckle back in place.

“Yeah. I see it, too. Just what in the nine depths has Adagio talked us into?”

“You’re asking that now?”

“Heh. Yeah. You think she Sang us into coming with that weird song?”

Sonata shrugged, shaking her head. “Maybe? I-I can’t remember it.”

“You can’t remember the song?”

“No. I remember she sang to us, and that’s all.”

"Huh. I do." Aria shrugged, spread her flukes, and darted after Adagio.

Sonata caught up to her a moment later. “We’re just going to do what she wants?”

“Why not? She’s got a plan, obviously, an insane plan, but she’s got one.” Aria glanced at her, shook her head. “Besides, if we don’t follow it to the end, then we’re all stuck here anyway.”

---

They found Adagio at the end of the corridor, at the entrance of a chamber so enormous that Sonata could not see to the other side, despite the pure silver light spilling out from six crystalline columns vanishing into a haze of silver light above.

Song runes, older than the script on the doorway outside, were carved into every surface save the pristine smooth crystalline columns, and hummed with continuous power.

In the center of the columns sat the oddest creature Sonata had ever seen. Neither seapony or land pony, and seeming constructed of the discarded bits of some mad statue-maker’s wildest fancies.

Only, it was not a statue. It was alive, and it watched them while seated in a chair made of wood, iron, and glass in equal parts.

“Oh, oh dear. It seems I have visitors! Please do pardon the lack of manners of the receptionist. He gets quite cranky.”

“What are you?” Sonata blurted, then slapped a hoof over her mouth. Adagio glared at her.

“Me? What am I? What are you, dear creature. I do seem to recall something like you some years ago… quite the nice—” He stopped, made a clicking noise with his left forepaw. “Oh yes, seaponies. Isn’t that what you call yourselves? Not hippocampi or mer-horses or any of that drivel, right?”

Sonata nodded mutely.

“Yes, I do recall, now. One of you came calling some seven or eight… well, maybe not years, it gets so hard to tell time down here when the only way to mark it is when you ponies make that awful racket. You still do that every year, yes? You haven’t gone biennial, have you?”

“Dad! Our dad was here?”

“Oh, so you were related? My condolences, then. He’s over there. Somewhere.” He waved a talon vaguely in one direction.

Sonata was darting away before he’d even finished speaking, calling, “Dad!”

He lay still, face gaunt, his flesh whole, but was silent, and his gills did not flutter in her wake. She didn’t need to press her cheek to his neck to know he was gone. She did anyway, and sang a soft song she remembered he liked from her youth. Still, he did not stir.

Aria touched a hoof to her back and drew her away slowly. “Mourn later,” she whispered. “We already have.”

“But he’s—”

“Dead as a doornail, still as a stump, kicked the bucket.” The creature rattled on for some minutes, listing what could only be euphemisms for death. “Yes. Yes, he is. So sad.” He chortled and raised a cup to his muzzle. “So droll.”

She jerked free of Aria’s embrace and slammed into a wall of force that sizzled as she touched it, and sent her streaking back into the stone wall, dazing her.

“Ah-ah. Musn’t touch,” he chided. “Now, why don’t you tell me. Why brings you here? It’s so rare I get visitors. Why, I can barely recall the last time, aside from that poor fellow”

Adagio swam up to within inches of the field, shimmering in the water in the wake of Sonata’s dash. “We came because I heard your call through the crystal. Oceana locked you away here, yes? Along with all of your treasures?”

“Treasures? Oh my. What do you think I am? A genie? A king?” He laughed. “I am a god, little ponies, at least, that’s what they named me. Mad, they called me, you see. The mad god of the sea! What did they used to call me? Oh, yes. Discord, I believe, for the muss I made of their music. Oh, wait… yes, they did call me king, once. The Tempest King, for some storm or another they claimed I was responsible for. Pah.”

“And then Oceana locked you away down here for all eternity.”

“Oh my, yes. With herself and her little chorus for company. But you mistake eternity, little one. Eternity is a blink of the eyes. It’s the moment that lasts an eternity, not the other way around.”

Sonata shook her head once more, still dizzy, and aching from neck to flukes, and looked up at the crystalline pillars. What she had thought were minute flaws were… she swam up to one, careful not to get too close, and peered into the hazy silver light. A pony’s mane floated inside, still as the fibers of a newly planted coralwood. Silver scales covered her lower body, and her face, in profile, reminded her of an old shell mosaic of—

“Oceana! She’s here!”

“Oh, no. She isn’t.” Discord sipped at his teacup, slurping away some of the ceramic. “Not really. I mean, if you want to get all technical and talk about spirits and magic and the like, go ahead and bore me, but she is no more here than I am a fish.”

“In the vision,” Adagio said, shooting a glare at Sonata, “you said that you could give us power. Can you do so?”

“Oh, did I say that?” Discord scratched at his chin, pulled off his entire muzzle and planted it on his backside. “I believe I was not quite speaking from the heart, you see.”

“What!” Aria darted up from Sonata’s side and tackled Adagio. “You said—you sang us down here, lied to us, manipulated us, and now we’re going to—”

“Oh, dear. Siblings fighting.” Discord’s smile widened. “No, no. You mustn’t. I will give you power like I said. Or, rather, I will let you take it. See, it is not mine to give.”

“Explain.” Aria shoved Adagio away.

“These ponies hold my power, not me.” He waved at the six shadows in the crystals. “Take my power back from them, and it is yours. But, a-hah!” He waved a talon at Adagio. “A condition. One pony to one pony. Those are the rules. Pity there aren't more of you.”

“Fine. I will take what is mine.” Adagio pushed herself up from the floor and swam up to Oceana’s still form, her voice already lifted in the strange, discordant song that she had sung earlier, the one Sonata still could not remember, already slipping away again even as she heard it.

“Oh, dear. You’re not so very good at this, are you?” Discord watched her, his mismatched eyes boring into her soul. “Sing along, then. Come here. I believe this one will suit you.”

She tried to resist, tried to swim away from the mad god, but his eyes held hers, still, and instead of away, she swam towards him and what could only be Swift Current, her lips locked in song, as it would be forever. Her song was weaker than the rest, and her form glowed a dull red in the light.

“Yes…” Discord hissed. “This will do nicely. Now, sing after me.” His voice lifted, a tearing scream of chaos that no earthly throat could produce, scouring her mind and flaying her soul.

But sing, she did, though the singing tore open her chest, only to be filled with ruby light. She could not stop, either the song or the feeling of her father's eyes on her, judging. She wept.

Daughter of the sea, fear not. This is merely another turning of the cycle. He will not win.

Swift Current was staring at her, eyes wide, knowing, and she smiled.

But... She tried to twist around, find her father, but the ruby light held her, searing into her breastbone, solidifying.

Worry not. He has passed on to calmer seas, as I will, soon. Thank you, Sonata, for taking up my burden.

Then she was alone with the pain, and screamed out the last words of Discord's song, vaguely aware that Adagio and Aria were likewise trapped, bound together, screaming out as the red light poured in, unable to stop the song.