A Russian nationalist by the name of Zakhaev is set on returning his homeland to the Soviet times. Zakhaev knows the United States would never allow this to happen, thus he funds a coup in the Middle East, organized by his ally al-Asad, to draw attention away from Russia. The two men and their seconds-in-command gain the nickname The Four Horsemen. However, the British and US governments have been monitoring Zakhaev's activities and discover his real intentions. The story is told from a perspective of a British 22nd SAS Regiment operative in Russia and American 1st Force Recon in the Middle East.
The game also features a flashback mission set 15 years ago in the Chernobyl Zone of Alienation, which features a new incarnation of Captain Price from 22nd SAS Regiment, the only character to appear in both of the first two games of the series. He needs to assassinate Zakhaev, but his mission fails because his Captain gets wounded and he has to get him out of the Zone of Alienation. Whether this new Price will be confirmed to be a relative of the WWII era Price remains to be seen. It is also believed that the assassination attempt had left Zakhaev with only one arm.