Gameplot

The game starts in Makin Island at night on August 17, 1942. Private Miller watches the torture and execution of a fellow soldier by the Japanese. As they turn towards Miller, he is rescued by his crew and they assault the island, replicating the Makin Island raid. The following mission then starts two years later, where the Americans assault the Japanese-held island of Peleliu. Miller calls in rocket strikes to take out Japanese Ha-Gō tanks. At the end of the mission, Sergeant Sullivan is fatally impaled through the stomach by a Japanese soldier wielding a katana. The next mission starts in a swamp area of Peleliu, with Corporal Roebuck (now promoted to Sergeant, after the death of Sullivan), as they travel to the Japanese-held airfield. Miller acquires a flamethrower and bazooka during the mission.

The mission Vendetta is only a singleplayer mission. The game then jumps to the Soviet campaign on September 17, 1942, during the Battle of Stalingrad. Dimitri Petrenko wakes up amongst dead bodies of his fellow soldiers, as the Germans shoot them. After they have gone, he meets Sergeant Reznov, who tells Dimitri that he wants to kill General Amsel, the man behind the Soviet casualties. After eliminating some German soldiers, Dimitri follows Reznov through buildings and streets, as they kill Germans on their way, using sniper rifles and machine guns, until Dimitri kills Amsel; at which point, they run and jump into the river. The following mission starts three years later at the Battle of the Seelow Heights, near Berlin, where Dimitri witnesses the torture of a fellow soldier by Germans and as the Germans approach Dimitri, he is saved by Soviet soldiers, including Sergeant Reznov. Together the Soviet troops advance through German lines, as Dimitri aids them with a Panzerschrek, as they reach a German camp.

The game returns back to the Pacific Theater of Peleliu, where the Americans are pushing further inland through the island. Miller and his unit take out enemy mortar crews, so their tanks can go inland. They then disable Japanese guns, facing out to sea by taking out enemy infantry in caves.

The following mission campaign returns to the Battle of Seelow Heights. Dimitri is at the controls of a T-34 tank, as he helps the Soviet Army to reach the train station by destroying German tanks. He, along with Reznov and the Soviet troops, board a train to Berlin. Upon arrival they engage German soldiers in buildings and around the streets, as the Germans are retreating. The following day, Dimitri watches a fellow Soviet execute a surrendering German soldier. They then move through buildings and streets clearing out Germans, until they reach the entrance to the Berlin U-Bahn. Dimitri is ordered to kill surrendering Germans there, although they are executed by other Soviet soldiers, if he does not. They head into the U-Bahn and start fighting German resistance around the platforms, until a surge of water engulfs the tunnel.

The mission Black Cats is only a singleplayer mission. The Battle of Okinawa is featured in the mission "Black Cats", where the player takes control of Petty Officer Locke, in a PBY Catalina flying boat. He destroys Japanese PT Boats and merchant ships from the aeroplane and then aids a U.S. fleet under attack. They rescue American sailors in the sea, while Locke shoots at Japanese PT boats and Kamikaze planes, until more US aircraft arrive. Miller and his crew make a ground assault on Okinawa after the aircraft mission. They clear out the Japanese from machine gun (MG) bunkers, allowing American tanks to progress. In the following mission they are ambushed while retrieving ammunition before starting their assault on Shuri Castle. Miller kills Japanese crew around mortars and the courtyards. Either Roebuck or Polonsky, depending on the player's actions, is killed by surrendering Japanese soldiers. The surviving Americans fight off a final Japanese attack and take Shuri Castle.

The penultimate mission starts as Reznov drags Dimitri out of the U-Bahn to regroup with Soviet infantry. They clear out buildings along a street to proceed towards the plaza outside the Reichstag, where Dimitri destroys Flak 88s and they take out the remaining German infantry, defending the entrance to the Reichstag. As they enter the Reichstag, they kill German soldiers in corridors, a lobby and the main room. After that, they clear out remaining German infantry on the roof of the building, Dimitri moves up to plant the Soviet flag. Before he can, a wounded soldier shoots Dimitri with a pistol. Reznov kills the German soldier, using his machete. Dimitri then plants the flag to show they have won the war.