Stories tell of a legendary soldier who, with Metal Gear in his command, had once waged war against the world. His name was Naked Snake, a.k.a. Big Boss. Now, in response to a world hungry for answers, the truth behind this legend will finally be told. Developed by legendary Hideo Kojima -- the mastermind behind the most successful video game tactical-espionage series of all time -- this game lets players take control of the famed Naked Snake at a critical junction in modern history. Advanced co-operative techniques allows multiple players to sneak into the fray and accomplish the mission together.
Four years after the events of the San Hieronymo incident, Big Boss—who prefers his original codename, Snake—and Kaz Miller have established Militaires Sans Frontieres, a small mercenary faction, on the Colombian coast. They are approached by Ramon Galvez Mena, a professor at the University of Peace, and his student, Paz Ortega Andrade. Galvez attempts to hire MSF to investigate an army that has discreetly occupied parts of Costa Rica. Snake refuses, identifying Galvez as a KGB agent, but is convinced when Paz plays a recording of The Boss. When Snake arrives in Costa Rica, he begins to suspect that the mystery army has brought nuclear weapons with them. Enlisting the help of the Sandinista Liberation Army, he tracks a shipment to a research facility deep in the mountains. His suspicions are confirmed when he witnesses Hot Coldman, a senior CIA agent, announce his intentions to fire a live nuclear weapon as part of a project code-named Peace Walker, a fail-deadly nuclear tank. Snake reveals himself to Huey Emmerich, one of Peace Walker's designers, who agrees to help him stop Coldman.