The First Alien War
1999
January 1st: The First Alien War begins.
Construction on X-COM's first base is completed. The base is well-equipped with several powerful RADAR units, a complement of well-trained soldiers, engineers and scientists, two rapid-response 'Interceptor'-class aircraft, and one 'Skyranger'-class troop carrier. The scanning equipment detects the first UFO within weeks, and the Interceptors are scrambled...
Over the next few months it becomes clear that X-COM is severely outclassed, but the soldiers and pilots bravely fight on. The Interceptors down the unwieldy supply craft, and the lightly armoured scout craft, with conventional air-to-air guided missile systems. Sometimes the alien craft are shot down or destroyed. Sometimes they turn and attack the Interceptors with some form of powerful energy weapon. More often they simply outrun their pursuers.
On the ground, X-COM meets even stiffer resistance. Soldiers protected only by thin kevlar vests and armed with little more than standard assault rifles are pitted against aliens with superior numbers, weaponry and armour. However, despite horrendous losses, the X-COM soldier's tactics win them through time after time. Dozens of alien craft - each a treasure-trove of advanced technology - are recovered. The research complement of the base immediately goes to work. Work begins on weapons incorporating LASER technology, as well as research into the bizarre alien weaponry, tentatively described as 'plasma'.
UFO activity increases across the world, and X-COM is forced to set up more and more bases across the world, in order to provide a greater scanning range, and shorter times to the interception of an alien craft. The funding provided every month by the Council of Funding Nations fluctuates severely as some countries gratefully increase their rates, whilst others lower them to indicate dissatisfaction with X-COM performance. Despite an overall increase in funding, X-COM soon needs to discover an alternative method of financing it's growth. The Commander strikes upon the idea of selling off excess alien technology, and even selling corpses to private researchers.
Meanwhile, the aliens similarly step-up their operations. Several cities come under attack from fearsome alien warriors. The initial 'grey' aliens are complemented by others, as the aliens begin to terrorise human cities, perhaps hoping to disrupt X-COM funding.
2000
X-COM continues to grow in size, experience and efficiency. Most countries are now content with the defence provided, although several countries do withdraw from the Council altogether. It is feared by X-COM intelligence that they are effectively controlled by the menacing alien invaders.
The scientists of X-COM persevere, and an understanding of the surprisingly simple principles behind the alien weaponry is reached. Results of tests and research summaries are recorded in the Commander's "UFOpedia" resource. Newly discovered weaponry is placed in the eager hands of X-COM agents, and they begin training with the new laser and plasma weapons. This, coupled with new armour based on alien alloy technology, makes X-COM ground forces the close equivalent of their enemies.
2001
The invaders begin to set up covert bases around the world. It is not long before X-COM chances upon one of these, and action is rapidly taken to eliminate it. The base is heavily defended, but the X-COM soldiers fight like fanatics, and the alien stronghold falls. As fast as they are destroyed, however, a new one is discovered. As more and more UFOs appear in the skies, X-COM intensifies research into more ways to fight back and resist.
2002
It is determined with great sadness by the top brass of X-COM that they are fighting an unwinnable war. They have intercepted hundreds of alien craft, and the ground forces have killed and captured nearly a thousand aliens, and a dozen alien bases have been annihilated, but the alien invasion is barely slowed. Scientists, interrogating captured aliens, confirm what is already suspected - the alien command is not based on Earth. It is decided that the new priority is to locate whatever is directing the alien war effort.
X-COM funding continues to plunge as more nations withdraw from what they have begun to see as a 'wasted effort'. Some nations, notably the richest such as the USA, increase funding to compensate. X-COM quartermasters continue to sell excess equipment. These two methods of financing operations are sufficient to keep X-COM alive, but they are no closer to defeating the aliens.
Then, X-COM ground forces successfully pull off an unparalleled victory. Alien commanders are captured, and the subsequent interrogations reveal the location of the alien command structure - at Cydonia, on the nearby planet of Mars.
Work progresses furiously on a new interplanetary craft, dubbed the 'Avenger'. The 'Avenger' is an X-COM gunship, capable not only of travelling through the depths of space, but also of going toe-to-toe with the largest alien battleships, and returning home victorious. As soon as an 'Avenger' is completed, and the very best X-COM soldiers assembled, the team is launched to attempt to destroy the alien leaders at Cydonia.
A short but intense battle ensues. The 'Avenger' evades weapons fire from alien defence batteries and combat aircraft long enough to land on the surface of Mars, within the alien base. X-COM soldiers pour from the transport, and immediately meet resistance from alien warriors. They fight their way to the largest nearby structure - an elevator, which transports the desperate survivors into the interior of Mars itself.
Grim tunnel fighting follows, and despite horrendous casualties in X-COM's forces, balanced against barely a dent in the innumerable alien hordes, a few armoured soldiers manage to struggle their way to the antechamber of the alien brain. The bizarre creature had apparently been single-handedly orchestrating the invasion effort. No more; X-COM shows no mercy, and the creature is vaporised. Without it's leadership, the alien hordes crumble before the armed forces of Earth, and are easily destroyed.
As the last of the aliens at the Cydonia base are being hunted down by the X-COM strike team, an automated distress beacon is activated. The last dying scream of the alien brain stretches across the void, penetrating Earth's atmosphere with ease. It is cut off within seconds, and scientists decide that it must have been a request for reinforcements from bases on Earth. These bases are either in ruins or are in the process of being captured by X-COM soldiers, so little more thought is given to it.
Once victory has been affirmed, X-COM's covert status is revoked, and information about their operations is released to the general public. The fact that a military unit had been battling the aliens for so long came as little surprise to many; grim-visaged soldiers had been seen in many major metropolitan areas over the last few years, fending off the alien invaders.
The first alien war officially comes to a conclusion.