 Genetically-engineered terrorists take over a nuclear weapons disposal facility on Shadow Moses Island in Alaska. They threaten to launch a nuclear strike if the United States doesn t give in to their demands: the remains of Big Boss, whose genes were used to create these "Genome Soldiers." At the head of this "revolution" are six former members of the disbanded special forces unit, FOX-HOUND, led by codename Liquid Snake, with his officers Revolver Ocelot, Psycho Mantis, Sniper Wolf, Vulcan Raven, and Decoy Octopus. The Pentagon sends in former FOX-HOUND hero Solid Snake, supported by his old commander, Col. Roy Cambell. His mission is to rescue two of the terrorists  hostages, and to find out if they have the ability to launch a nuke, and stop them if they do. Soon after infiltrating the base, Solid Snake discovers that the nuclear warhead storage facility is only a cover-up for a deep underground base used for the development of a nuclear launch-capable walking battle tank, called Metal Gear. Knowing this, he ultimately sets out to destroy FOX-HOUND and Metal Gear. As he carries this out, he finds out that he has been double-crossed by his support and pursued by a crazed former ally and enemy. Friend and foe are indistinguishable as he discovers the reality of his mission, the terrorists  plot, and the story behind the mysterious resemblance between Solid Snake and Liquid Snake.