In [insert country here, thinking of Switzerland] Several archaeologists found unknown material while digging. They sent it to scientist to finds out what it was. They found out it was unknown and began to experiment with it. The project is called Project Sphinx and they created a new type of weapon. The UN finds out about this, and declares they make the project public and stations several task forces from different countries to stand guard over it. The [insert country here] is unhappy with this and stages a mock riot and forces the task force to kill some people. Using this they declare war and try to get the task forces out. You are part of the task force, and after going to safety in another country, you are sent back to retrieve the project sphinx. Unfortunately for you, (near end of campaign) when you get to it, it blows up on you, mutating you, and you have to get out of the caverns where it is hidden. It has partly caved in form the blast.