On February 25, 1968, SAD/SOG operative Alex Mason is strapped to a chair in an interrogation room. Unaware of his whereabouts, he is bombarded with questions by his unseen captors about the location of a numbers station. Most of the missions in the game are presented as the flashbacks of Mason between 1961 and 1968.
In 1961, Mason, Woods, and Bowman attempt to assassinate Fidel Castro during the Bay of Pigs invasion of Cuba as a part of Operation 40. Mason apparently succeeds in the assassination, but their exfiltration goes awry, with Mason staying behind to protect the extraction plane. He is captured by the real Castro, having shot a double. Because of an alliance with the Soviet Union, Castro hands Mason over to General Nikita Dragovich. Mason is then held captive at Vorkuta Gulag for two years. During his imprisonment, Mason befriends Viktor Reznov, a former Red Army soldier. Reznov recounts to Mason the identities of those involved in Masonâ€™s torture: Dragovich, Lev Kravchenko (his right-hand man) and Friedrich Steiner, an ex-Nazi scientist who defected to the Soviet Union. All three share a connection to Reznov: in October 1945, Reznov, Dragovich, Kravchenko, and Dimitri Petrenko were a part of a unit sent to locate Steiner, hiding with a unit of the SS in the Arctic Circle. During the operation, Reznov was betrayed by Dragovich, who used Steiner's creation, a nerve agent known as "Nova-6" on Petrenko. Reznov was spared the same fate when British commandos attacked the Russians. During the confusion, he destroys Nova-6. However, it was later recreated by Steiner and a British scientist named Daniel Clarke for the Soviets. Shortly afterward, Reznov is imprisoned in Vorkuta. Mason and Reznov spark a prisoner uprising to escape the gulag, but only Mason escapes.