In Call of Duty 4, the player assumes the role of two characters in the fictional war that takes place in the game. Sgt. John "Soap" MacTavish, a member of the British S.A.S. and Sgt. Paul Jackson, a member of the United States Marine Corps. Though missions for both characters take place in different locations they are both fighting toward the same goal; to stop the terrorist forces of Khaled Al-Asad and Imran Zakhaev from using a nuclear weapon they have obtained.

In Call of Duty 4, the player assumes the role of two characters in the fictional war that takes place in the game. Sgt. John "Soap" MacTavish, a member of the British S.A.S. and Sgt. Paul Jackson, a member of the United States Marine Corps. Though missions for both characters take place in different locations they are both fighting toward the same goal; to stop the terrorist forces of Khaled Al-Asad and Imran Zakhaev from using a nuclear weapon they have obtained.