I had this dream about the world ending, but I'm putting a twist on it. Demigods are known in the mortal world and are hunted ruthlessly for experiments in the genetics and mutagenetic departments. I do not own Percy Jackson, but Louisa is my OC.

It was a fairly normal day, the sun shining outside and their P.E teacher forcing them to swim in almost freezing temperatures and at least a hundred metres. The pool was square and the tiles lining the bottom of it were brown. Most of the large, square room was brown, including the low ceiling.

A trio of girls sat to the side, trying to hide from their evil sports teacher, Ms Baker. Her limp, dull blonde hair was drawn back in a high bun. She had beady, blue eyes, thin lips and a hawk nose.

Strangely, there was a section near the girls that dropped down into the school's water supply. A back-up escape route should the need arise. It hadn't yet, but it was there, ready and waiting.

"Do you reckon he's down there?" Ellie sighed dreamily.

"Oh yeah, 'cos the school's dream boy hangs out in the sewers." Louisa rolled her eyes. Ellie's blue eyes hardened in annoyance.

"Just because you couldn't care less about boys doesn't mean you have to dash other people's hopes." She freed her long, thick mouse brown hair from its ponytail and fashioned it up in a loose bun. "And I asked him to meet me here." Louisa looked at her other friend, Molly.

Molly was shy, often hiding behind her dark hair and peering cautiously at people with her deep blue eyes.

Molly gave a timid smile and looked down.

"Molly, would you rather stay in a warm, clean classroom or go trekkin' around the sewers to find some desperate girl?" Ellie scowled at Louisa. Molly's smile broadened slightly.

"I'd prefer the classroom." She said quietly. Louisa nodded in agreement.

"Louisa!" Louisa groaned. Their teacher had taken a liking to Louisa as she was a natural strong swimmer and skilled diver. Every so often, Ms Baker would grant Louisa a break from swimming, which resulted in Louisa worming her friends out of the sport too.

Louisa loved swimming. But her teacher took it too seriously. Louisa may have been competitive, but she saw swimming as a form of entertainment. She did not want to end up like her teacher.

Ms Baker called her again. Louisa sighed.

"Teacher's pet." Ellie teased. Louisa smirked and Ellie looked worried. She had every right to be worried as Louisa wasn't one to annoy. If you upset or angered her, she would happily get her own back.

Louisa got up and stood at the end of the pool, in a line with a few other girls in her class. None of them looked happy. None of them could get from one end of the pool to the other without stopping occasionally. Louisa could do that and back without stopping.

While Louisa swam, Ellie glanced back into the water supply. Water tumbled out of sight beneath them and gurgled busily. Louisa had a point about the school's dream boy remaining in a classroom instead of walking through the water that churned and flowed so fast, it could easily knock anyone off their feet.

Ellie pulled her gaze away. She and Molly watched their friend reach the other end of the pool shortly before the others. Louisa twisted underwater and kicked off the wall. Most of the other girls had to stop and turn, not entirely keen on going underwater. Ellie was like them. She would change into her swimsuit, but would do as little swimming as possible. It was tiring and the water was freezing. How Louisa managed to swim perfectly well in that climate, she wasn't sure. Louisa was someone who took anything life threw at her. If life gave her lemons, she would make super lemons.

Molly tapped Ellie's shoulder and pointed.

Ellie frowned. Behind Louisa, something had broken the surface.

A fin.

It was a dull orange-brown colour, jagged and fairly limp. It was nearly as long as Ellie's arm.

"Miss!" Ellie shouted. The teacher looked round, her usual scowl in place. "Something's behind Louisa!" The teacher looked, but the fin had disappeared. All that could be seen was a dirty peach coloured blob, distorted by the water and following Louisa.

Louisa suddenly dived and the blob followed. The teacher shouted at the students to get out of the pool, which they did all too gladly.

The pool was twelve feet deep. Louisa was known to reach the bottom and stay there the longest out of all the girls. Once it had been ten minutes, in which the teacher had dived in to make sure Louisa hadn't drowned. Louisa, however, had been fine and had waved cheekily at their teacher.

Louisa clambered out of the water as it exploded behind her. Screams went up, but Louisa remained calm, a fire burning in her eyes.

The dirty peach blob had surfaced. Whatever it was, it was hideous. It had a long snout, with huge, jagged pincers in its mouth, dripping with water worryingly tinged green. It's large, bulging grey eyes were oddly bird-like, studying everything with a three-sixty turnaround. It was at least ten feet long and seemed to have eaten two small cars for breakfast. It had a tail like a whale's, but a fin along the end, similar to the one on its back.

The thing pulled itself up onto the side, showing it had frog limbs and webbed feet attached with long, curled, dangerously and frighteningly sharp claws as dark as obsidian.

The abomination's terrifying eyes shifted and focused on Louisa. Louisa met the gaze with a defiant glare, one she reserved for bullies.

Louisa took shit from no-one. And that clearly extended to hideous beasts as well.