Whoever thought this was a good idea is terribly foolish
Normally when Kili lost a bet it meant he had to do something ridiculous like eat a raw fish head or work on deck in a tutu and tiara. Normally when his friends talked him into doing something incredibly stupid it involved lots of alcohol and possibly weapons. One time it involved trying to race to the top of the fishing boat while eating a raw fish head with only the left side of their bodies. No one won that competition, or that time they decided they were going to decorate Christmas trees in the middle of an empty parking lot near the docks and then tried to Molotov cocktail them. Turned out it was really hard to light trees on fire when it was the middle of an Alaskan blizzard.
Granted these were all very dumb and dangerous things none of them came close to actually dying. Well, working in the fishing and crabbing industries could be quite dangerous and had killed people before, but he had never been trapped to drown under hundreds of feet of water. This was the situation he now found himself in with some of his friends and an adventurous team of scientists who wanted to explore the bottom of the ocean.
Kili had spent his life on the water, joining his uncle with his brother at a young age to learn the art of fishing in Alaskan waters. When his mother made him and Fili stay home from a trip out to sea he learned other practical skills on land; family friends in the neighboring Alaskan region were more than willing to teach metal and wood working to them and the mechanical things they learned made Fili and Kili both well equipped to handle engine troubles on the massive ships they worked on. While it was their ambition to one day have their own ships, for now the brothers were perfectly happy sailing with their uncle, Thorin. Decades at sea made him an expert fisherman, and while Fili and Kili were still young and inexperienced, he knew that one day his nephews would be worthy and capable of inheriting his prized crabbing vessel: The Lonely Mountain. Nicknamed "The King's Jewel" by other experienced captains, she held a long history of successful runs that made all the crewmembers quite rich at the end of every season.
But Fili would carry on the Durinson family name without him Kili thought to himself as he leaned his head against the metal wall of the submarine his was in. He heard large creatures moving around the ship he was trapped in, odd clicks and calls that didn't sound like anything he knew.
He was here because of two of his friends, Bran and Collin, who had met a couple of marine biologists at a bar and after a few drinks had agreed to join them. Or maybe they were marine geologists. Geographers? Something damned that involved going to the bottom of the ocean looking for things they shouldn't be looking for. Something about a shipwreck or something that would make them all rich and famous that sounded appealing at one point, but no longer.
Kili looked out the small window and saw nothing in the darkness of the ocean depths except for odd glowing lights. The lights flashed and moved in the water, pale bioluminescent light that was attached to whatever sea monster was trying to kill them. They had lost propulsion and power over 20 minutes ago and had been sinking ever since. Whatever was out there continued to hit the sub and sometimes there were terrible grating sounds like something running claws over the outside of their tiny pocket of air and warmth.
"You owe me a grand." Kili didn't look at Collin, watching the lights that were probably his doom out in the water. Bran snorted and Kili heard a punch behind him.
"I bet that we would find something, and we found something!" Bran protested, not interested in losing a thousand dollars.
"Something found us," Kili said softly before he turned ever so slightly to look at his friends in the emergency lighting.
"I think we all lost," he said after meeting their gazes in the red glow. With that solemn statement he looked back out the window. At first they had fought, tried to get free of what they thought was a pod of whales that appeared from nowhere. But then the slamming started; whales don't start ramming into submarines for fun. Sharks don't either, but whatever was out there had slammed into them until they began spinning and damaged their engines. It was a miracle that whatever it was hadn't punctured the hull and drowned them all immediately, but it was pulling them down deeper where the pressure would surely kill them. He had already tried to fix the power and the engines but the damage was outside; there was nothing he could do from inside this sinking tin can.
The lights outside were multiple creatures, he could tell that much from how they moved independently of each other. Whatever they were, they were long and slender with dots of light going down their bodies. Or maybe it was lighted tentacles of some hell spawn squid. Kili put his hand up to the glass, looking at his death, and gave a sigh.
And then he yelped in surprise when he saw a face on the other side of the glass.
"The fuck?" Collin asked, looking.
"Didn't you see? It was a face, there was a person out there!" Kili exclaimed as he pushed his face up to the window to see better. But the face was gone.
"Oh great, sirens are going to kill us? Should I plug my ears?" Bran scoffed, his normal humor somehow intact. Maybe he was just imagining things, but he thought he had seen the face move to the right…
"Where are you going?" Collin called to Kili as he moved down to the next porthole.
"The sea witch cast her spell, and he's in love with her!" Bran declared. Kili said nothing, staring out the next window into the swirling lights and darkness.
"Actually, Bran, I… have something to tell you…" Collin said sheepishly. Kili gave them a glance, wondering what had come up, but Collin nodded toward an empty room and Bran followed him while asking what was up.
When Kili looked back out the window there was a hand on it. This time he didn't shout, instead staring in curious wonder at the five-digit hand. It was webbed and looked like it was covered in hard scales and it had long spikes for fingernails. But it still looked like a human hand. That couldn't possibly be right.
Kili reached out and touched the glass, his hand matching the one on the outside, and was startled when the face reappeared.
It looked human, the red from the light within the submarine casted it in a hellish glow, a woman's face with thick hair swirling around her. There were lights on her face, little dots of light that lined her bone structure.
It tilted its head to the side, looking at him, its large eyes staring right at him as though he were a bug in a jar to gawk at. Although perhaps, to it, that's exactly what he was. But he was doing his share of staring right back, mesmerized by the face on the other side of the glass. Something startled her and made her swim away, and whatever that something was hit the side of the submarine with enough force to spin it again, causing Kili to slam back into the wall behind him.
He passed out on the floor, spinning with the submarine as it flipped in the water.
Coughing. Coughing and gasping for breath and terrible pain in his head and salt in his mouth and he was alive.
He was alive.
Kili's eyes shot open as he rolled over, coughing and feeling dizzy and trying to see in the darkness. What was below him was water and rock, smooth stone with a few inches of water rippled over it. In the water appeared to be bits of light, and as his eyes adjusted he looked around the cave he was in. It was covered in some sort of bioluminescent algae. There appeared to be no way out, the lights formed a uniform dome around him, but he felt too sick to stand up and try to figure out how much space there was. His eyes continued to adjust to the point where he could see his hands, albeit not very well, but when he tried to get up it resulted in making the headache even worse.
He didn't know how long he was in the strange cave alone, but after what felt like hours he managed to sit up so he was no longer lying down in the cold water. He sat in the water, shivering and numb. Why was he alive? How had he gotten here? Were the others still alive? The pounding in his head was something for him to focus on so he wouldn't worry about how numb he was; it was something to keep awake and alive. He was in pain but as long as his head still hurt then he was still alive. And still being alive meant being able to escape and survive. Somehow.
The water rippled and he felt something disturb the water to his left. He felt sluggish as he turned his head, knowing that he was well on his way to having a serious case of hypothermia. In the water were lights; it was one of the things that had been circling them. But now he was able to properly see it as it swam toward him.
The thing was long, maybe even ten or twelve feet long, with what he thought was a dark grey color to its scales. But the tendrils, or maybe it was hair, he could guess were a dark red color. The tail it had was vertical, indicating that it wasn't a mammal but a fish of some sort. A fish with human like arms and hands and face, right, because that made sense.
Clearly he was still really drunk and he was going to wake up and this would all be over soon.
He recognized the face was the one he had seen before, but it no longer looked like a face from hell as the light on it was no longer red. Its face was pale, practically white, and definitely looked like a woman's face. Except for the fact that it glowed with bioluminescent light. It looked up at him from just beneath the surface of the water, watching him inquisitively. It made the last swish of its tail and extended its arms, pulling itself out of the water and onto the barely submerged rock next to him. But it didn't touch him, instead getting extremely close to him, as though it wanted to be touching him but couldn't do it. It opened its mouth, revealing pointed teeth, and clicked at him. If Kili had to venture a guess it was trying to say something, but all he could do was shiver and rub his arms with his hands to try to keep warm. It crawled around him, circling him when he said nothing to it, and then became transfixed on the air coming out of his mouth in condensed puffs. It gently extended one of its hands to try to touch the breath as it came out of his mouth and pulled back its hand when it felt the heat but could not touch it. It tilted its head to the side again, looking at his face, and clicked again. When Kili remained silent it rolled off the rock and into the water, disappearing from sight.
What surprised Kili was when the same creature appeared again, this time with something in its arms. It offered a mass of… something to him, looking at him expectantly.
"Don't… understand." Kili managed to say through chattering teeth and a foggy mind. It seemed startled that Kili was able to make sound, perhaps it had thought that the shivering and his clattering teeth were his way of talking. But it seemed to get the idea as it dropped the load next to Kili, pulling itself up around him again.
"Hey-! What-?" Kili managed, trying to move away from the thing as it tried to put whatever it was on him. The creature just curled tighter around him so there was nowhere to go, and began to cover him in what felt like thickly woven seaweed. It was cold, clammy, slimy, and made him shiver even more.
"Stop … freezing…" Kili tried to say as he started to lose his vision and awareness. For a few moments he felt himself going completely numb and was only vaguely aware that something was rubbing his arms, legs, chest, back, and head.
When Kili opened his eyes again he was looking up at the face of the creature, he felt the now warmed seaweed blanket wrapped around him and the fish's body coiled tight around him like an eel. He didn't feel as cold anymore and he realized that the hands he had felt earlier weren't his friends trying to wake him up from being passed out, it was the thing trying to keep him warm. Why would it do that?
"Thanks." He managed, not sure if he should move or if he was now the thing's favorite toy. It tilted its head, perhaps pleased that he was now once more conscious, and uncurled from him and jumped back into the water.
"Wait!" but of course he was calling to ripples, the thing was already gone.
It only left him alone for a few minutes, however, before it returned with a fish in its mouth. Its arms held it propped up on the ledge of the rock, but it extended its neck and dropped the dead fish in front of Kili. It looked pointedly down at the fish and then back up to him.
"I can't eat that," in response the thing picked up the fish and took a bite of it before offering it back to Kili, this time holding it in its hand. Kili shook his head.
"I can't eat that," he said again, slower, as though that would make it understand. It dropped the fish and grabbed for the blanket it had given him, making Kili jerk back in fear.
"No! I need this!" Kili shouted, but the things claws already had its nails in the seaweed and it tore a small section free. It then took a bite of the seaweed before it offered it to Kili, apparently unfazed by Kili's alarm and violent jerking. Kili sighed, realizing this thing was going to keep bringing him things to eat until he did so. Bracing himself he took the strip of seaweed from its offered hand and took a bite. While it was slimy and salty it was also warm, and even though he wanted to gag he was also freezing and hungry. It seemed satisfied that he was eating based on its long tail flexing out of the water.
"Thank you," Kili said after he had choked down the seaweed. It blinked at him, staring at his lips as he said it. Then it extended a hand, touching his lips and throat, its hands getting tangled in his beard.
"Uhh…" Kili glanced around but it looked up at his eyes and then back at his lips as if waiting for something.
"What do you want?" Kili asked. It splashed its tail and got up out of the water, curling around him and facing him all the while looking at his lips.
"Can you stop?" when Kili tried to back away its hand followed and Kili watched when it raised its other hand to its own mouth and throat. It clicked again.
"Can you speak?" he asked it. Its tail flicked, slapping the water.
"Kkkhee," it said, or tried to say.
"You can speak?"
"Seeeehhkkee? Keeeh?" at its second attempt it got angry, jumping back into the water. It swam around the rock he was on a few times, making more sounds that he could not understand through the water. It finally stopped in front of him, keeping its neck in the water but its face out and looking at him. He noticed its hand was still on its throat.
"Do you have a name?" Kili asked, not expecting it to be able to say anything.
"A name. Nnn. Name," he said slower, leaning down and emphasizing how he was pronouncing the word. It started at his mouth, watching the way his tongue moved.
"Yes! Name. My name is Kili. Kili," he said his name the second time slowly, pointing to himself.
"Keeeleee?" it questioned, trying to understand him. He nodded and smiled before he pointed at himself again.
"Kili," it said, pointing at him. At that Kili pointed at the creature and wondered if it would understand.
"Tarrr-" it began before it stopped and slapped the water with its tail.
"Taarrrel," it hissed and splashed, trying to say its name to him so that he could understand. After several more attempts and laps around him clicking to itself it finally managed to say:
"Tauriel?" Kili said slowly. It splashed the water, rose up out of it, and pointed to itself. It seemed pleased that it had been able to convey its name. Then it sank back into the water to the level it knew it could communicate with him. It seemed to be dissatisfied trying to speak with its gills out of the water but he couldn't understand it when it was completely underwater. But it smiled up at him, or at least tried to. It looked like it was baring his teeth at him. The attempt made him laugh and smile again. It tilted its head at the sound and tried to smile again. The second attempt at smiling was much better.
"So mermaids are real?" Kili asked. It tilted its head and its smile faded as it grew confused. But Kili didn't expect it to answer him anyway.
"Never thought you were real, and now I get to meet one before I die," he looked up at the ceiling of the cave, dotted with light.
"Reminds me of stars," he began to ramble, and Tauriel pulled itself up next to him and looked at the ceiling.
"It will be summer soon, you wouldn't be able to see the stars for a while because of the midnight sun. Mom always liked that Fili and I wouldn't be able to sneak out of the house in the dark of night since there was no night," at that thought he reached into a pocket and pulled out the stone his mother had given him as promise he had made to return home. Tauriel looked with interest at the rock but didn't touch it.
"My mother gave me this, she thought it would protect me, bring me home when I went out to sea. Looks like I won't be going home…"
"Home?" Tauriel said the word slowly.
"Where I live, on the surface," he pointed up but didn't know how to explain it to the mermaid.
"Tauriel," he said, sticking his hand into the water and motioning toward it.
"Tauriel's home," he said for emphasis before he lifted his hand out of the water and pointed up.
"Kili's home," it followed his hand motions and seemed to understand.
"My home is up there, on land, on the surface. But I can't go home. It's impossible," he said, his gaze upward.
"Wait- STOP! NO-" Kili screamed as he was suddenly drug under by Tauriel. The water was freezing and knocked the air right out of him. Its arm was strong around his chest but he thrashed and kicked it away. He broke through the surface and scrambled up on the rock, freezing cold once again.
"Kili! Home!" Tauriel called to him, pointing down into the water and then motioning upwards. Apparently it had tried to take him out of the hole it was using to enter this cave. Kili shook his head as the intense shivering returned.
"I can't go that way! I'll drown! I'll die!" he shouted back to it as he coughed up water he had inhaled. Tauriel seemed upset by his distress and quickly pulled itself next to him and covered him in the seaweed once more. Kili did not lose conscious as Tauriel made quick work rubbing heat back into him and the seaweed blanket. That did not keep his breath from becoming labored as the headache got worse and he did not fight when Tauriel curled its body around him. This time he was able to feel its heart beating through its green gray chest, and he realized he could feel something under the mat of red hair. Was Tauriel a female? Why would a fish have breasts? But then Tauriel was humming, emitting a low pulse and a repeating series of clicks. Was that a siren song? Whatever it was, the sound accompanied by the warmth Tauriel had rubbed into him was making him drowsy. As much as he tried he couldn't help but fall asleep in the mermaid's arms, lulled to sleep by the humming in its chest.