The year 2002. The war is over. The aliens had been defeated and X-Com stands victorious. However, the Earth and humankind were not left unscarred. Even with numerous technological advances made during wartime, the overall losses are horrible. Many territories are polluted by alien activities, many cities are left in ruins and many lives are lost. And to make everything worse, most of the new technology is heavely dependant from Elerium-115 - which is extremely rare and is not indigenous to Earth. Since the only known Elerium source is downed alien crafts, the new Gold Rush has begun. But with so many people chasing one thing, the situation quickly went out of control. Numerous private treasure hunters and corporate salvage crews invade every country in the world, completely ignoring everything (including the law) in their pursuit of wealth and often curb-stomping the local police and even armies with superior xenotech weapons and armor.
Meanwhile, X-Com, that grew from an alien defence agency to the largest xenotechnology manufacturer and dealer, was unaffected by this new crisis. Independent from any goverment thanks to its wealth and superiour technology, X-Com traded alien tech almost to everyone interested and secretly gained much power and influence. As the Elerium Rush started and hotspots covered the entire globe, X-Com came out of shadows and proposed themselves as UN peacekeeping force and xenotech control agency. Left without any other choice, UN agreed and soon X-Com, operating under the corporate name G.R.E.S.O. (Global Reconnaissance and Extraterrestrial Salvage Operation), came back in action. Within next ten years almost all UFO crash sites on land were secured and salvaged, and the Elerium Rush seemingly came to its conclusion...
...But not really. Altough a lot of non-govermental salvage groups had been wiped out by G.R.E.S.O., there were others who were more careful and chose a more stealthy way. Many UFOs downed during the war ended up on the seabed and stood there, not found by few undersea X-Com bases and rife with valuable alien artifacts. While G.R.E.S.O. was occupied dominating the surface, these groups proceeded to salvage these alien wrecks under water without any interruption. However, as surface Elerium caches had been claimed by the goverments with the aid from G.R.E.S.O., the undersea scavanging became more and more desperate, often resulting in bloody clashes between rival salvaging bands. Some were desperate enough to attack sea labs and even X-Com floating bases, hoping to steal their Elerium stock. Others were preying on cargo ships and island warehouses, essentially becoming pirates.
G.R.E.S.O. responded with brutality. Its subdivision, S.O.R.E.S.O. (Sub-Oceanic Reconnaissance and Extraterrestrial Salvage Operation), hunted down each and every known non-govermental salvage team until no one was left. This series of underwater military operations was later named the Great Undersea War - and was another victory for X-Com.
However there were still numerous unresolved problems for humankind to deal with. The enviroment suffered greatly both from the previous wars and post-war rebuilding. Uncontrolled urban growth, overpopulation and global unemployment resulted in the world-wide political crisis of 2015 that ended only in 2027 with only 16 global goverments left. Hoping to deal with overpopulation by establishing space colonies, G.R.E.S.O. tried to persuade the world nations to use most of Elerium supplies to launch a manned mission to Mars. Their initiative, however, was rejected out of fear of exhausting Elerium stock completely - even with recent successes in developing a substitute for this extraterrestial mineral, Elerium was considered far too valuable to waste it for fuel. But instead of space colonies an alternative plan has been proposed - to build a massive underwater city-stations to house the populace. There, deep beneath the waves, people would be safe even if the aliens were to attack again...
Year 2037, present day. A great portion of humanity now dwells under water, protected by S.O.R.E.S.O. The invention of the Fusion Power helped mankind to overcome Elerium dependency, and since then the technological progress went far away from its xenotech origins. However, Elerium and alien weapons still have some value on the black market, and S.O.R.E.S.O. keeps watching over any salvage operations and investigating any suspicious activity, still ready for alien comeback - especially since something unusual is going on recently. Increased pirate activity, strange sightings, misterious dissapearances of naval vessels and aircraft, reports about never-seen-before alien artifacts emerging on the black market and a cryptic final message from suddenly imploded and sunken Khimtar submarine ("They are here! They are among us!") - all these events are linked somehow. Perhaps it is not the right time to abandon the X-Com legacy...