Plot

The game is set in the early 21st century during a fictional world war between various power blocs: the United States aided by the European Union, the United Kingdom, and the Russian Federation at war against China and the fictional Middle Eastern Coalition (MEC) aided by various insurgent groups.

There is no known reason as to how or why the war broke out, though one likely theory is for control of oil reserves. In-game, the European Union and the United States fight China and the MEC. It is mentioned in-game that the US and EU are allies and the EU has negotiated a peace deal with Russia, but it is unknown if China and the MEC are allies. The game also takes place in different fronts, as the Middle East and China are being invaded by US and EU forces, and the United States are being invaded by Chinese and MEC forces.

(From Wikipedia)