The story of Battlefield Online is set in an alternate timeline to The War in Battlefield 2. In this timeline, the Middle Eastern Coalition had been selling huge quantities of oil and natural gas to the United States and Russia. A conflict soon broke out between the two superpowers over the fuel sources. The nations of the former Soviet Union as well as China soon joined Russia in an attempt to expand their borders. The European Union thereby allied with the United States to try and slow the opposing forces progress.