This is the first story I can remember finishing writing. It was for a secondary school English assignment. We had to write a Sci-Fi story which I remember being excited about while the rest of the class was much less enthusiastic. I think, there also had to be a twist at the end too. The last modification on this one before my grammatical correction before putting it here was 09-03-2013, which would mean I was 13 and in year 9 at school when I wrote this. Reading it back I'm kind of surprised how dark it is and how well I managed to capture such a depressing tone considering I remember actually being quite happy at this time in my life.

There are a few weird sentences that would maybe be a bit better reformatted, and I'm not sure the extended metaphor at the end quite works but this was a good effort from 13 year old me and I think I got a pretty good grade for it too.

Chapter 1: Depression

Marty walked along the dusty path with each metallic clank. He had just left his workplace, “hell”, or at least he thought of it that way. Government work was drooling and hard in 3066. The world which Marty lived on was like many others these days. People breathed artificial air produced by the government workers in places they called Airiators. Marty worked in one of these places. He hated his work. He sat there all day pressing buttons, trying to manipulate plant genes to produce more oxygen. The air was mustier than when the Airiators were first set up, they allowed people to breathe easily even when plant life had been severely wiped out. The need for this was the metallic jaws of destruction that had eaten it all. The government. “If they hadn’t made this mess, then there would be no need for the Airiators, and I wouldn’t have to work in those forsaken places.” Marty thought as he kicked up some dust on the track leading towards the bar; he headed there to drink away his long-lasting gloom.
Before, he had not needed to do this. Before the dome. Before the industrialisation. Before he lost his wife. All he had to do then was watch animals to see how they were doing; he was a healer to them. A miracle maker. He used to be a vet, but now with his degree in biology, all he could do was work in the Airiators. Work in hell. 
Soon, he found himself at the old shack of a bar ironically named the Modern Dog; it was made entirely of steel, whilst everything else was made of pure platinum. Rusting on the outside where the artificial rain had landed, whilst the skyscrapers loomed around it, shining like they had just been polished. It stood only twenty meters tall while all the other buildings peeked almost touching the dome. The dome encircled the planet. It had been put up when the ozone layer was getting extremely thin, it was supposed to be a substitute for it. No one really knew how it worked, and it was hard to get off the planet because you could not pass through, and so had to go to one of the very few cities with an air dock. Marty didn’t care much about the Dog’s architecture as long as he could buy a cheap drink there. He stepped inside, met by the usual stare of the bar’s customers; he didn’t pay much attention to them and instead walked on with his usual beaten-down stagger to be met by another man. One he had not seen in a long time.
The man stood eight feet tall, a giant of a man, looming over Marty his teeth covered in scum however he still had a beaming smile on his face. Hair almost dripping with grease as though he had not washed for weeks, cut into the style of many a commoner. He had rather rugged-looking clothes and looked ready to run a marathon. The pair looked like an odd couple standing in the middle of the bar, for Marty was almost the complete opposite of this man. He had long, elegant hair in a brownish shade and rather nice-looking clothes, for although not the best place to work, the Airiator workers got paid a lot, and he had relatively clean-looking teeth. 
Greeting like an old friend should the man roared, “Marty!” in a merry fashion, paused a moment, then gave him a friendly pat on the back. He waited for some form of a reply, but nothing. Marty just stood there, mundane. “Oh, come on lad, what’s up?”
“Nothing”, Marty replied “Nothing's up. Everything’s down, everything is bad; I mean, I work in the Airiators” 
“It could be worse, look at you, reasonable pay, nice house and stuff. You could be a dome cleaner, they have to go up there and risk their lives cleaning the dome above us.”
“I know, it’s just if they had never destroyed everything, all the plants and wildlife, there would be no need for the Airiators anyway or the artificial rain or any of this.” Artificial rain was invented before all of the plants were destroyed, so that they would continue to be nourished even when the sea was covered over and built upon. Now it was more of a burden than anything; something to remind people of the past, it was never taken down because it would cost more to take down than to leave it. “Oh come on lad you can’t just throw your life away because a little thing changes, it’s like throwing your car away if the windscreen wiper falls off” argued the man “anyway Marty, I’ll buy you a drink that’ll cheer you up and I need to speak to you about a job that’s came up”

Chapter 2: The Job

“Look, Zero, I don’t want to go on one of your stupid jobs. I’m no criminal.” Zero Marty’s old friend was a bounty hunter, one who worked outside the law's jurisdiction. Zero sat there on the table. In one hand he had his beer, the other lay by his side, his legs were propped up by the table in front of him. Marty sat opposite with a rather rigid posture. “Marty, you’ve not even heard who it is yet, you can’t just say no before I’ve even filled you in on the contract,” exclaimed Zero
“Go on, then, what unlucky gentleman is it this time?”
“This Gentleman is the Emperor.” The Emperor was the ruler of the whole planet, a dictator in many a man’s eye; he was the one who ordered all of the forests to be cut down, and the seas to be built over. The entire planet was a city now.
“Wait a Minute, the Emperor who rules the planet, who covered the oceans, who made the artificial rain and the Airiators.”
“That’s the one lad,” said Zero “So you in?” There was a short look of thought upon Marty’s face. He knew that bounty hunters like Zero were often convicted, but he hated the Emperor, the dictator over the planet, the devil. “Yes!” he said like a child excited for he had just been invited to a birthday party. “The contract came up about a week ago, as soon as I heard of it, I knew you’d be in. My plan is that we get maps of the Keep off an informative friend of mine, then from there we plan our route to the emperor. Obviously, we’d need the Emperor’s schedule, but that shouldn’t be too hard to get; it won't be easy, but we should be able to pull it off!” The keep was where the Emperor held all his meetings, lived, and quite literally did everything else, it was his world. He liked to give things names with a medieval theme, although this planet was far past that stage. 
“It’s getting late, we should return home. I’ve got work tomorrow,” announced Marty 
“Alright, meet me here after work tomorrow. I’ll show you where my headquarters are and we’ll iron out the kinks in the plan” Marty did so straight after work, he went straight to the Dog. Zero was already there, he looked rather cheerful as always. Marty approached him. He had thought about the idea of ridding the world of the Emperor. Was it possible? Was Zero crazy? Zero greeted Marty in the same way he had the day before, and then he led him to his Headquarters.
It was in a rough part of town where most of the buildings were made of old rusted steel, like the Modern Dog. Most of the buildings here were only about ten meters tall and looked as though they had been abandoned years ago. Few people were on the streets, probably for fear of their lives or working long shifts. After about ten minutes, they came to an alleyway. There seemed to be no accessible buildings hear, but Zero said, “Right here we are.”
“But this is a dead end!”
“No, it’s not you’ll see.” Zero said whilst pulling the top off a door knob, from a door which lead to someone’s yard, to reveal a button. He pressed it. Nothing happened. Then, after a few moments of silence, came a whoosh, the scream of a banshee. The floor in front of them opened, and steps led down farther than you could see into a dark abyss. Flickering the lights then came on, showing all of what was before devoured by darkness.
The corridors seemed a bit less dishevelled than the streets above. “Zero must be a bit wealthier than I realised before; this bounty hunting business must be worth it.” Marty pondered, Zero led him through the maze of plain thin corridors until they came to a door which seemed to have some form of pass code. The corridors were rather bland, however, they were made of a more valuable type of steel than the one on the streets above. Zero punched in the password, saying, “Welcome to the headquarters; this is where we’ll be working from whilst we get information and make our plans. If you need one, there‘s some rooms just down the corridor, people on my jobs often use them.”
“I think I’ll just stay at home for now,” Marty said with a nervous tone.
“Okay, then let’s get this plan sorted then!”

Chapter 3: The Plan

Marty woke up in his room, which he had now decided to stay in for convenience. He could only do this until the Airiator, which he worked in, was fixed. It had been having more and more faults recently, and then one day it just broke down. He would have to work again when it was fixed. He got out of his bed with covers which looked as though they were from the 2980s, the room wasn’t as bad as Marty had thought it would be. It was quite clean, and although the furnishings, a bed, a steel dresser and a rusting wardrobe which the roof leaked onto, weren’t exactly to his taste, he liked it, it was different, maybe a bit odd. But he liked it. He only ever really used his room for sleeping anyway.
Not too long later, he was in the room which he and Zero used for planning, confirming what they had decided the day before. They came to a decision using the information they had obtained from various informers, who lurked in the dark listening like bats, that they would attempt to assassinate the Emperor tomorrow. Using the multiple maps they had collected of the keep’s vent systems and corridors, they plotted an almost perfect route to the Emperor’s chambers. They would follow this route at a time they had worked out from much watching of the Emperor. The Emperor was always in his room every day at this time. Going through a particular vent system to get into the Keep, about ten minutes before, Marty and Zero would arrive at his quarters, passing all guard patrols, when the Emperor was alone in his quarters. At least if everything went to plan.
They would go in armed with knives so that they could kill silently, cats stalking their prey. Just in case they would take laser pistols in case their plan went wrong and things got messy. Although they believed they would not have to use these. Everything seemed perfect, they just had to carry out the plan. The Emperor, the kid bully at school, would be gone, expelled, and everyone would be freed from his evil shenanigans.

Chapter 4: Taking Action

The next morning, they woke up early and prepared themselves for freedom. Making sure not to forget anything, they began gathering the supplies they would need to kill the Emperor. When they were finished with that, they left the Headquarters and began to head towards the Keep, making sure to be at the specified vent at 9:50 AM. This was ten minutes before the Emperor would be in his room, ten minutes before he would be killed. Assassinated by Marty and Zero.
Crawling through the vents, the two of them began to follow their route towards the Emperor. The vents were a trachea about to breathe and push them out. Three minutes later, they reached a corridor. No one was there as planned. They were a virus trying to spread through the body and strike. Now they would simply walk down the corridor until they reached the next vent, which they intended to use. But then, unsuspected, a White Blood cell came rushing at them in the form of a guard. Zero whipped out his knife to fight back against the cell. The blow hit. Piercing Zero’s enemy’s protective suit and digging into his heart. Blood spurted as he removed the knife. Zero made sure not to let any go on the floor, then threw the body down the vent and followed it. Rushing after him, Marty said, “But... the p..plan, the... there shouldn’t have been anyone there!”
“Things don’t always go to plan.” Zero said quietly whilst pushing the body down the opposite tunnel in the cross-section.
Soon they reached the Emperor’s chambers, the heart of the organism. Zero whispered, “Let’s hope no one else saw us apart from that guard before, or we’ve got no chance.”
Marty didn’t say anything; he was too nervous to speak, and he just stood there dumb. Waiting. Zero sighed, then said, “Let’s get this over with.” He pushed the vent hatch off and jumped down into the Emperor’s chambers below. Marty followed. There he was, just sitting there, his back facing them, another cell for the viruses to conquer. Had he not heard them? They edged closer. “If you kill me now, the whole world will perish,” Croaked the Emperor “You will have no way to stop it.” Although he didn’t show any sign of resistance. “And in what form would this disaster come?” Zero said sarcastically. “I cannot tell you that, all I can say is that if you kill me, you will also kill yourself.” The Emperor still seemed calm. Zero turned to Marty, “Kill him!” Marty stood there for a moment, dumbstruck. Here was the man who had brought chaos to the cycle of nature and his life, yet if he killed him, things could become worse. Killing this man couldn’t make things any worse than they already were, could it? He had decided. He ran up to the Emperor and ran his knife right through him. Things didn’t seem right. Marty looked at the desk the Emperor had been sitting at. The computer was flashing. It said, The end is imminent, The end is imminent. 
Both Zero and Marty began to suffocate. The antibodies had fought them off, but not the ones in the keep, the ones of the world. They were killing everyone who had infected it. Had taken it over. Everyone was suffocating, all the air had gone, and now the humans lay there dead, like the world they had infected. Planet Earth lay there dead.