In 1964, CIA agent Naked Snake is sent to Tselinoyarsk, USSR. Aided by his superior Major Zero, medical advisor Para-Medic, and his former mentor The Boss, Snake is tasked with rescuing Soviet scientist Sokolov, a prominent weapons developer who defected two years ago until the Russians forced the United States government to return him. Zero informs Snake that following his return, the CIA received intel that Sokolov is placed in charge of a secret military project to create a nuclear-equipped tank called the Shagohod, which could end the Cold War. Although Snake locates the scientist, the mission falls apart when The Boss appears before him and announces her intention to defect to the USSR. While her special forces unit, the Cobras, recapture Sokolov for their new benefactor, Russian officer Colonel Volgin, the Boss defeats Snake in close combat, seriously injuring him and leaving him for dead. Volgin swiftly captures the Shagohod, which was being tested in the region, and uses a Davy Crockett nuclear shell supplied by The Boss to destroy its research facility and cover up the theft. The injured Snake is recovered via fulton extraction, moments after the nuclear blast.
