Call of Duty: Modern Warfare 3 is the eigth game in the Call of Duty series and the third in the Modern Warfare series.
The player can play as a member of Task Force 141 and the Green Berets. The playable character for Task Force 141 are Daniel "Gator" Benson, and for the Green Berets Cpl. Nick Garret. Returning characters are Price and Nikolai. Markarov returns as the main antagonist.
The game begins directly after Modern Warfare 2. Soap, Price, and Nikolai are hiding in Ethiopia with the remainder of Task Force 141 when an attack by Shadow Company forces them to flee to a base in Australia. Realizing they'll die if they don't clear they're names, they head a Shadow Company base in Pakistan, downloading information from a computer. The information is revealed to the US President, who takes control of the 141. The conflict then goes to Manhatten, where Garret and his unit are sent to clear Central Park. They then head to a Russian intelligence base in Maine, where they find that chemical attacks are being planned by the Russians, and they are going to get if from an arms dealer from Kazahkstan.
The Green Berets head to Kazahkstan to destroy the chemicals, but they discover that they were already shipped out to agents in London, Paris, and Berlin. Back as Gator, the 141 head to Markarov's hideout in Estonia. He escapes, but the 141 discover his right-hand man, Yuri, is hiding out in Berlin and is going to direct the ground attack. The Green Berets also head to Berlin, and the two factions cross paths. The 141 manage to gain the Berets trust, and the information is pieced together that the Russians will use the chemical agents to conquer mainland Europe and Great Britain. With the chemical agents already destroyed in Berlin, the 141 head to London while the Green Berets head to Paris.
Much of the world now believes the 141 is innocent, but Markarov decides to continue the fighting. In London, Gator takes out a train carrying the gas with an RPG, ending the threat in London. The Green Berets have less luck, and the gas is activated, slowly spreading through Paris. The Berets head to the tunnels below Paris and destroy the area that is releasing the gas. The Berets use a truck to escape Paris. With the war in America over and the operation in Europe unsuccessful, the Russian President plans to sign a peace treaty. However Markarov takes control of Russia and orders the Russian military to continue attacking Europe.
Markarov's location is guessed to be at either the Kremlin or in Leningrad. Both locations are attacked, but it is discovered that he is at neither. Price then remembers that Yuri said that a Plan C would be at Dubai. After attacking the heavily fortified city, Markarov escapes on a helicopter, with the Berets and 141 in hot pursuit. After Gator takes down Markarovs helicopter with a Valkerie Rocket, the 141 go to investigate the crash. It is revealed that Markarov is still alive and running away. Gator is ordered to take the shot, and only a head shot will take Markarov down. After taking the shot, the bullet is followed as it kills Markarov.
The world then celebrates the end of World War III.