Water splashed up around Sam’s ankles. The sand, soaked with sea foam, squelched between his toes. He sat on the edge of a rock, letting the waves wash up onto his legs. The water glowed a spectacular range of orange and red, but Sam found himself unable to enjoy it. The monotonous, washing sound of the ocean drowned out everything else.
“That was really immature of me,” Katy said. She was sitting cross-legged on the sand, flipping through the pages of her favorite book. She’d calmed down a little since her outburst.
“Who cares. It’s easy to see your mistakes in hindsight; the hard part is figuring it out before you make them,” Sam said.
“Wow, that was actually really deep for you.”
“Shut up.” The siblings sat in silence for a little while. Suddenly, Sam jumped to his feet.
“All right, no use feeling sorry for ourselves. We’ve got this whole island that we’ve never seen before. What do you say we go off exploring?” He said.
“It’s almost night. If we stay out too long, they’ll start worrying about…,” Katy trailed off. She jumped up to her feet too, ignoring Sam’s yelp as he almost got headbutted.
“Alright, let’s do it,” She exclaimed. Sam nodded and followed her off the beach and into the forest.
“Hey, look over here,” Katy yelled. Sam backed away from the monstrously huge, gnarled tree he was inspecting. In the dusk light of the forest, every root, rock, and thorn became nearly deadly. Sam carefully threaded his way towards his sister’s voice. After he had threaded his way past a nasty looking pricker bush, only to trip over his own feet, Sam stumbled into the clearing. Katy was kneeling on the ground in front of a rock formation.
“I found another cave,” Katy said. She excitedly brushed her hair out of her face and rummaged around in her backpack. After a moment, she drew out her phone. It was one of those old flip-phones, with a chipped case and cracked screen. Nevertheless, it was one of the only things they had left of their parents. The old thing had used to be mom’s, and after she had died, Katy hung onto it. Now, she clicked open the screen and, with a flare of light, activated the flashlight. Sam winced at the sudden brightness.
“Nice,” He said, “Hey, can I go first this time. You got to go first for the last cave.”
Katy just smiled and crawled in. Sam followed her in with a sigh. The inside of the cave was dark and cramped. The moist walls pressed against Sam’s sides, leaving a slimy residue on his hands. As they crawled along, the dank smell of the cave assaulted their noses. Pretty soon, the only light came from the measly wattage of the flip phone. Thankfully, neither of the siblings was claustrophobic.
Sam wasn’t sure how long they’d been crawling along, before he realized that the passage had widened. Katy stood up first.
“Now this is much better,” She said as she stretched out her arms, “Now we can really do some exploring.”
Sam rose to his feet, too.
“Oh man, now I know what being an old man feels like,” He muttered as he rubbed his back.
“Stop complaining. This is the most excitement we’ve had since you angered that drug dealer’s daughter, and we had to hide in your girlfriend’s closet for three days. Come on, this is fun!”
“Ha, you have a screwed up idea of excitement. What you call ‘fun,’ I call a pain in the neck. Literally.”
Both their voices echoed through the cavern.
“How far down do you think we’ve gone?” Sam asked.
“I don’t know. It’s hard to tell, judging by the incline. It’s pretty slight, so I don’t know how long we’ve been going down,” His sister replied.
“How much longer are we going to keep going?”
“Until we reach the end, obviously.” With those words, Katy started off again. Sam followed, muttering about how she was supposed to be the responsible one.
They kept walking on. It was hard to tell distance in the near darkness, so they didn’t know how long they’d been trudging on before they emerged from the tunnel.
The first thing Sam noticed was the feeling. So far, even though he hadn’t been touching them, he could still feel the walls around them. It was like the walls had their own atmosphere, and once they emerged into the cavern, that atmosphere changed. Both Katy and Sam stopped in their tracks. Katy turned phone’s miniature flashlight up as high as it could go, and strafed it around.
Both the siblings stood open-mouthed and dumb at the sight before them. The cavern was huge, hundreds of feet wide, and nearly as tall. Stalactites dripping with moisture glistened on the ceiling. Beneath them, huge stalagmites rose up, some of them looking like miniature versions of the Tower of Pizza. Taking up most of the cavern was an underground lake. It was huge, and filled with perfectly calm and translucent water.
“Woah, I wasn’t expecting this!” Sam said.
Katy looked at him, and huge smile on her face.
“This is so cool,” She whispered. Sam started wandering forward slowly.
“Yeah, I’ve never seen anything like it. Do you think anyone knows about gyaaa,” Sam yelped as he tripped and fell to the ground. He fell on his hands, wincing as they were skinned against the rough, stone floor. As he slowly crawled back upright, Katy burst out laughing.
“What are you laughing at?” Sam asked, in a voice that could have frozen magma.
“Sorry, Sam, that was just hilarious. I mean, you screamed like a little girl!” She chuckled.
“Shut up,” Sam muttered as he turned around to look what he’d tripped over. Laying on the ground in front of him was a stack of wooden crates. It looked like he’d knocked the lid of one of them askew when he tripped over it. Sam rose to his feet, and went over to investigate.
“I guess that answers the question of whether or not someone knows about this place,” Katy commented. She trotted over to join her brother. Sam glanced into the crate, and pulled out a glass bottle. The glass was dirty, and covered in a patina of age. A clear liquid sloshed inside as Sam held it up to the light. He studied the cracked and peeling label on the bottle.
“Huh, what is this? Ethanol?” (Maybe use something else, ethanol is kind of a weird choice) He muttered to himself. Katy took in a sharp breath.
“Hey, Sam, don’t drop that bottle,” She said.
“Huh? Why not?”
“Ethanol is a highly flammable liquid. From the looks of that stuff, it’s probably been here for a while. It’s probably unstable, so don’t..,” she stopped as she watched Sam hurl the bottle as far away from himself as possible. It hurtled through the air, before splashing down into the lake. The water rippled as the bottle disappeared from sight.
“What the hell! Don’t just tell me out of nowhere that I’m holding a bottle of dangerous chemicals. What if I’d dropped it?” Sam yelled.
“Well, neither of us has an open flame. We probably would have been fine. Speaking of dangerous, what are you thinking of, throwing a bottle of chemicals like that? If you thought Ethanol was really dangerous to us, you shouldn’t have chucked it,” Katy objected.
“Yeah, well I threw it into the water, so we would’ve been safe anyways.”
“You don’t know that! For all you know, Ethanol reacts with water to form poisonous gas.”
As if to emphasize Katy’s point, the water in the center of the lake started frothing. Bubbles rose from around the banks, as the mirror-like surface was broken.
Both siblings just stood there for a second.
“Does it?” Sam asked slowly.
“No. And if you’re asking, I’ve got no clue what this is,” Katy replied. The surface of the lake was getting even more choppy. Small waves sloshed up against the shore.
“Maybe we should get out of here,” Sam said.
“Yeah,” Katy said. Neither of them made a move, though. They were staring, transfixed, as something rose from the center of the lake.
It was a long, slender object that tapered into a triangle at the tip. It kept rising out of the water, getting taller and taller. The dark grey surface was slick and shiny. The object eventually stopped growing at a height of nearly 20 feet. It resembled the sail of a boat, and wavered back and forth in the air.
“What is that?” Sam asked “What the heck is that thing?” Katy just stood there gaping.
Then, the object started to fall over. No, it wasn’t quite falling, it was bending like a flexible straw. It slammed into the water with a sharp slapping noise, and sprayed water everywhere. Katy and Sam slowly backed away, wiping the briny spray out of their eyes. Then, the sail, or whatever it was, rose slowly out of the water again.
That was all Sam cared to see. He snatched Katy’s hand, and took off, dragging her behind him. She let out a yelp as she was tugged off her feet, before finding her balance again. Soon, she overtook him as the siblings took off pell-mell through the near dark. They bumped off the rock walls as they darted through the cave. Not even their panting breaths could drown out the sound of the mysterious object slapping into the water again. Water sprayed all around them in an explosion worthy of a Seaworld Performance. Katy screamed.
Suddenly, Sam spotted the exit. The tunnel lay hidden in the rock wall in front of them.
“Down here!” Sam yelled. Katy scrambled quickly into the tunnel, followed closely by Sam.
It was almost immediately obvious that the tunnel they were going down wasn’t the same one that had started out in. The ceiling to this passageway was much higher, and the walls were covered in slime. But, neither Sam nor Katy were willing to go back to find the correct one. Whatever it was in that lake was more terrifying than being lost. All the siblings could do was hope that this passageway would also lead out to the surface.
They wandered along in stunned silence for a little while. Finally, Katy interrupted the quiet.
“Freaky,” She whispered.
“No kidding. What was that thing?” Sam replied, just as quietly. For some reason, whispering just felt right in this situation.
“I don’t know. I mean, I really don’t know. It feels like something out of a Science Fiction novel,” Katy said.
“Yeah, maybe. Or maybe I’ve gone crazy or something.”
“You’re not crazy, I saw it too.”
“Yeah, but you could also be part of my delusion. For all I know, I’m standing in a corner, muttering to myself.”
“You aren’t crazy, Sam.”
“That’s just what one of my delusions would say. Gah, all this self-doubt is hurting my brain.”
“Stop making jokes,” Katy snapped, “We need to focus.”
“Sorry, couldn’t help it,” Sam muttered.
Suddenly, both of them registered the sound coming from in front of them. It was a deep, rumbling, sloshing noise.
“Yeah, it’s the ocean. We must be near the exit!” Sam called. They both took off at once. It didn’t take them long to reach the end. However, instead of reaching the exit, they ran into a wall of sheer stone: a dead end.
“Why?” Katy asked quietly. She’d stopped, and now just stood like a brick in the middle of the tunnel. Sam shoved past her. There was a layer of groundwater on the floor, and it rose up around his ankles as he walked forward. The water in here was so cold that it sent pinpricks of pain through his legs. However, he kept going.
“Come on Katy, we’re almost out. There’s salt water here, and we can hear the ocean, so we must be really close,” He said. Then, the ground dropped out from under his feet. It was so sudden, that Sam only had time to take in a quick breath before his head plunged under the water. The shock of the cold caused him to cough, and reflexively breath in. As his lungs burned with saltwater, Sam clawed his way to the surface. He crawled up onto the rock ledge, coughing and spluttering.
“Sam,” Katy yelled. She splashed over to join him. (This next bit might be a little sudden, decide if you want to change it).
“I’m fine,” Sam choked out, “I just swallowed some water.”
“No, not that. You might have just found the exit!” Katy said. The relief on her face was almost palpable.
“Thanks for your sisterly concern,” Sam muttered. Katy ignored him and shone her light down the hole. It was five feet in diameter, and actually looked pretty round. The rock inside it was worn smooth by the water. It looked like it descended a few feet, before heading off to the right. They couldn’t see anything after that.
“How long do you think it continues for?” Katy asked.
“I don’t know, probably not that long,” Sam said, “It doesn’t seem like the wall in front of us is too thick.”
“Yeah, but it’s pretty risky. Who knows how long we could be stuck down there, and if something happens, we’ll end up drowning.”
“It’s either this, or we go back.”
“I guess so,” Katy said. She nodded, and motioned him forward.
“Fine,” Sam said. He took a few deep breaths, and plunged headfirst into the water.