The year is 2662. Humanity exists beyond the confines of its origin. The Sol system has been largely terraformed and most of the plants have a healthy population. Even the gas giants, such as Jupiter, enjoy a thriving colony in great ringed stations around its mass. Thirty five years ago, humanity faced a threat like nothing before in its existence.
It started slowly, a few long range scout groups stopped reporting back. Then some science colonies on nearby star systems went dark. A task force was assembled to investigate and assess the cause behind these events. Humanity's leaders were troubled; having dealt with a variety of space-borne viruses and bacteria, they wanted to know if a new infestation was occurring in the outer reaches of their domain.
Their task force, a mighty armada comprised of warships and research vessels alike, reached the far-flung star after months of journeying and initially reported back the all-clear.
Then they went silent too.
The brightest minds humanity had to offer came to a consensus that mankind was no longer alone in the great void of space. With the task force's prime directive being quarantine, there was no way that something of a microscopic nature could bring down the entire battle group. No, it appeared as though the ultimate question had been answered, mankind was not unique among the stars. There was someone else.
Orders were given to create the greatest fighting force ever mankind had ever seen. All available factories were converted to war-time use; pumping out starship after starship, munitions rolled off the line at the rate of millions per hour. Forces were conscripted from all planets, anyone over the age of 18 who was not actively engaged in essential work, was trained and sent to serve their brethren in the skies. In total the combined output of the Sol system managed to produce a little over 23,000 battleships, carriers, destroyers, and smaller support craft when the enemy arrived.
June 6th, 2627. A Tuesday, of all days, is when it happened. At 10:43AM Earth Unified Time multiple slipspace ruptures were detected along the fringes of the system, just inside the Oort Cloud. Actual numbers were unconfirmed, with much of humanity's military structure destroyed that day, but estimates place the enemy force at roughly 5,500 supercarrier analogs. Massive vessels housing thousands and thousands of strike craft each.
The alien force moved inwards quickly, wiping out outposts and stations as they went. They met in battle with mankind's assembled fleet near Lagrange Point 3. Huge battleships opened fire with their rail cannons. Accelerating volleys of 4 ton titanium sabots to 0.1c in milliseconds (67,061,662.9 miles per hour). These relativistic projectiles tore angry gashes in the alien fleet, rending their carriers, and simply atomizing clouds of strike craft.
But the invaders had no intention of slugging it out at extreme range. Their force continued to close on the defending fleet, seemingly unfazed by unfathomable amount of kinetic energy thrown their way. Within minutes, they were practically on top of earth's fleet and began unleashing their own salvos of pure plasma. Giant orbs of angry light smashed into the battleships, melting through feet of armor like acid through skin. Their munitions didn't rely on mass or concussive force; no, these slow moving spheres just ate away at whatever they came into contact with. A plasma ball would splash along the hull of a ship, and continue to melt away anything matter it came into contact with until it dissipated.
Scores of earth ships were left as drifting hulks in the first few minutes of the battle. Lifeless titans slowly traveling whichever way inertia demanded, venting atmosphere and bodies into space like a macabre pinata. Debris followed the silent warships like tattered angels, escorting the crumbling behemoths on their eternal patrol.
It wasn't a completely lopsided battle, however. While the armor of earth's ships was useless against plasma, the inverse was true with the alien hulls. Railcannon rounds, missiles, and even point defense cannon fire met little to no resistance as they plunged themselves deep into the gargantuan alien ships. Later, it would be discovered that the material of their armor plating was designed to absorb plasma, not kinetic or explosive forces.
Upon the realization that the enemy was in just as precarious of a position as they were, humanity rallied and began to develop strategies on the fly for quickly disabling the aggressing supercarriers. Human strikecraft, outnumbered nearly 1,000 to 1, were recalled; their rockets and missiles unloaded for use in the capital ship's batteries. Swarms of smart missiles were quickly found to be better at eliminating the alien strikecraft, than wasting precious human lives in a dogfight they couldn't win.
The battle began to turn in humanity's favor, if ever so slowly. Still taking massive losses themselves, the humans watched as the alien ships closed ranks in more of a defensive posture. Emboldened by the scene that lay before them, humanity fought on harder than ever, determined to rout these uninvited guests from their home.
They nearly succeeded too.
That is, before the alien's main fleet arrived.
No official numbers were ever tallied of the full might of the invading force as most of the outpost picket stations were destroyed in the enemy's initial march through the system. What is known, is that the slipspace rupture was so large, that a giant hole stayed open in space for awhile. A visible tear in the fabric of reality.
A low level technician on one of the remaining picket stations had the presence of mind to point a laser scope into the giant rend, acquiring valuable data for the now overwhelmed defenders. A group of forty scientists of various disciplines working under the stoic gaze of Commander Stanis Everett, and aided by scores of AI, thought they might be near a solution to the problem of the alien's reinforcements.
As the battle raged on in space, humanity's numbers began to dwindle. Fighting a battle of attrition now where only minutes before they were all but victorious. While they were still defeating enemies at a healthy ratio, now having learned how to evade the slow moving energy projectiles, the sheer numbers put their skills at a massive disadvantage. The order was given to fight to the last man, unleash every weapon in the stockpile. Everyone knew that there was no winning this fight. They were too unprepared, too unequipped, and far outnumbered.
In a last ditch effort, Commander Everett authorized the deployment of Project Bulwark, a theoretical way to dissolve slipspace within its activated radius. It had never been fully tested, and never intended for this scale. The station that Project Bulwark resided in was quickly re-positioned nearer to the sun where it could receive direct power from the partial dyson shell covering a few million square miles along the sun's southern pole. Transmitting that kind of energy was incredibly dangerous and could easily overwhelm and destroy the station outright, but the station would be destroyed regardless if they didn't try.
Hundreds of technicians worked in concert to adjust the focal arrays capable of receiving stellar power, and hundreds more quickly adjusted relays towards the core of Project Bulwark. And then, when his kind was down to only a couple thousand remaining ships in the Great Fleet, Command Everett pressed the activation button.
The core in the center of the station began to glow as it was fed power directly from the star. Absorbing nearly 4.8 x 10^17 gigajoules per second the great machine screamed with unfathomable power as it activated its slipspace nullifying wave. A photon from the sun would take nearly a month to reach the innermost borders of the Oort Cloud, but the Bulwark wave traveled through slipspace, collapsing it as it went. It met the unholy gash in space and time where the aliens were entering Sol and eradicated it from existence causing a massive flash of light and a wave of destruction obliterating the alien reinforcements. Still to this day, nearly 35 years afterwards, the light is still visible to earth and her colonies. A new star in the sky and a reminder that humanity is no longer alone in the cosmos.
Relativistically speaking, the instant the slipspace rupture was nullified the alien armada began to drift listlessly in space. Still very much alive, but behaving in a state of utter confusion. Later it would be discovered that the aliens operate in a sort of hive mind, and by breaking the connection to their compatriots, Everett had single handedly rendered the invading force inert.
An hour or two of sheer slaughter followed as mankind eagerly laid waste upon the remnants of the alien force before, an act of unfettered benevolence, High Command ordered a ceasefire. Boarding teams were sent out by the hundreds and captured the remaining foes along with their technology where they would remain sequestered on Io for the next 20 years.
Slowly, clean up efforts began in the Sol system, many of which are still in progress 35 years later. Wrecks were salvaged when possible. The most ravaged ships sent on a stellar trajectory or allowed to drift outside the travel lanes between planets.
Everett eventually rose to power, progenitor of this new era of humanity. All along, promising to never let Bulwark station founder; it's invisible barrier keeping humanity safe from certain doom. After two decades, Everett allowed the alien population, now know as the Rhen'Kai, to mingle with humanity. Effectively cut off from their hive mind, they learned to live as individuals and became members of society, albeit slightly distrusted by those who had survived the war.
A new era of peace enveloped the Sol system. Humanity prospered under Everett's leadership. Still, vast sums of taxpayer money was funneled into the United Earth Military, growing their forces even larger than the original defending force. Never again would mankind fall prey to the unknown.
The the slipspace event near the edge of the Oort Cloud was known colloquially as 'Everett's Horizon', much to the chagrin of the scientists who actually conceived the device that caused it. The Horizon was an interesting topic of study as space around it had become non-Euclidean and was rife with temporal distortions and other vagaries that defied the known laws of physics. It was thought that these things would remain in place so long as the Bulwark was emitting its slipspace nullifying waves. This meant humanity was safe, but a door is closed to those on both sides of it.
Humanity constructed a giant halo of radio telescopes, vigilant sentinels to watch the frontier where they could no longer tread. Ever listening for anything that might be out there.
But as time passed, the younger generations and those born after the Battle of Sol, grew more and more complacent...