The Fourth Alien War

2084

A serious threat to the city of Mega-Primus is discovered on the 7th of March, 2074. X-COM personnel, conducting a routine security sweep, discover a bizarre phenomena in the skies over the city. Almost instantly, the anomaly expands, and a craft of unknown origins appears within it. The UFO is trailed around the city by X-COM craft, unsure of whether or not to engage. The craft passes over several buildings but does little else. Finally, it returns to the anomaly, and disappears. This event is repeated several times as more small craft appear and move over the city, often at night.

Basing their studies upon research from the Frontier, an X-COM science team containing some of the GSC's best minds determines that the anomaly is a gateway to another dimension. On the 11th March, a MegaPol police officer reports that an unknown creature has been discovered, in the back alleys of a residential estate. The beast is considerably different to anything seen before. Acting quickly, an X-COM team is despatched. The soldiers clear the area near the sighting, killing several blue humanoids and a few small, orange aliens which leap from eggs. Thanks to the heavier armour X-COM is now equipped with, casualties are rare and injuries minor.

Once the aliens have been met on the ground, and found to be hostile, the next UFO that appears is attacked by X-COM's aerial forces. Several unmanned probes and scouts are downed, captured and researched. In response, larger alien craft appear, some terrorising the city with powerful beam weapons and missiles, others attempting to locate and destroy X-COM bases, and some teleporting alien infiltration squads into corporate buildings. Research quickly reveals the secrets of alien breeding habits, and it is discovered that left unchecked they breed like bacteria. Many city buildings are swept and cleared of all alien life, and in some vast colonies are found. Many X-COM agents lose their lives, but eventually the city is deemed clear - until the next UFOs appear, that is.

As more and more larger alien craft begin to appear in the skies over MegaPrimus, X-COM purchase unoccupied warehouses and slums, setting up bases in the underground areas. Research into captured aliens and salvaged technology continues - and it is rapidly determined that these are not related to the aliens previously encountered by X-COM.

The research reveals the chemical composition of the alien body, and a cheap synthetic toxin is found to be highly effective against alien lifeforms, killing them nearly instantly. Work begins on more advanced forms of the toxin. At the same time, research into alien technology reveals the secrets of disrupter technology. Not only does this give X-COM the sue of alien disrupter and devastator weapons, it also allows them to develop the ultimate in lightweight protection - disrupter armour and personal shields. The fight on the ground begins to turn in X-COM's favour, despite alien innovations like the dimension missile launcher and the horrifying entropy gun. The war in the skies is much tougher, and many X-COM craft are lost. Work begins on a new X-COM craft, beginning with research into UFO propulsion and navigation systems. This indirectly leads to the development of a drive system which will allow safe transit through the "dimension gates". A probe is retrofitted with one of the drives, and passes through the gate.

Later that day, the probe reappears, battered but intact. The data it carries with it reveals an astonishing thing about the aliens; everything about them is based on biological technology. It had already been seen that their spacecraft were almost entirely organic, as were their weapons, but it amazed many that the entire alien city was one vast organic entity. Every one of the grown alien buildings served a distinct purpose - and therein lay their weakness. X-COM decided that the destruction of certain buildings would impede alien efforts to assault humanity.

However, they have to act fast. Alien attack ships, bombers, even battleships and the terrifying motherships - itself as big as the largest building in MegaPrimus - have assaulted the city. Half of the city is razed to the ground, and despite construction crews repairing the worst of the damage fairly rapidly, MegaPrimus' economy was drawing closer and closer to the red line. X-COM retaliated, the latest Explorer, Retaliator and Biotrans vessels transporting heavily-armed assault crews into the alien dimension, where they successfully attacked, disabled and destroyed alien buildings. The fifth and sixth buildings to fall dealt the aliens a mortal blow; their ability to construct craft was lost. This was no consolation to the hundreds of thousands of civilians, and the scores of X-COM pilots and police officers, who has already lost their lives.

The X-COM fleets no longer have to perform surgical strikes on the alien buildings. The fleet masses, and swarms through the dimension gate. On the other side, the remnants of the alien fleet musters for a last feeble defence. They are utterly annihilated. However, unknown to the X-COM fleet, a suicide fleet of a pathetic few alien craft has already fled through the dimension gate, into MegaPrimus. There they have laid waste to several buildings, as MegaPol patrol cars attempt in vain to destroy them. The X-COM fleet, headed by the new Annihilator craft, returns in time to crush the alien ships as they move to threaten the Senate building. More names are added to the dead, but X-COM's resolve only hardens.

The final attack is planned. X-COM agents enter the final phases of their training as they prepare to assault the dimension gate generator which allows the aliens access to our dimension. Once that building is destroyed, the crippled alien civilisation will surely perish in the wastelands of their ruined world. The X-COM Annihilator vessel is equipped with transport modules to carry as many agents and as much equipment as is possible. The soldiers equip themselves with shield units, cloaking fields, teleporters, toxiguns, vortex grenades...

X-COM makes the final assault armed to the teeth. Despite heavy alien resistance around the gate itself - half a dozen of the towering megaspawn are found, as are several insidiously powerful psimorphs - X-COM crushes the last alien warriors in less than two hours of vicious combat. Each of the thirty generators projecting the gate into the sky fails and, unsupported, the gate slowly begins to fold in on itself.

The victorious X-COM prepares to depart. However, the last few aliens, cowering in the ruins of the generator, intend to ensure that their deaths are not in vain. They initiate the self-destruct of their building, and as the generator tears itself apart in a thermo-nuclear explosion, X-COM troops hurriedly board the Annihilator and flee. Several do not make it, and their bodies are never recovered as the Annihilator swings about and flees, riding the crest of the blast, heading for the collapsing dimension gate. But despite the incredible supersonic speed of the Annihilator, the shockwave is still faster, and it steadily gains on the craft. The Annihilator has almost reached the shrinking gate when the shockwave hits it.

Back in MegaPrimus, X-COM despondently survey the ruins of their once-great city. Buildings are in ruins, and those that still stand are scarred and burnt by the vicious firefights that have plagued the city. Derelict vehicles litter the streets; the construction vehicles are too busy to clear them away.

But hope has not yet died - something that X-COM remembers as the blackened and charred X-COM Annihilator bursts from the collapsing dimension gate, streaking to the ground on a trail of fire, skidding to a steady halt on a ruined highway. The assault teams had survived the toughest ordeal imaginable.

Humanity could too.