Metal Gear Solid 2: Two years after the Shadow Moses Incident, Solid Snake and Otacon — operating as Philanthropy — receive intelligence about a new Metal Gear being moved up the Hudson River. As Snake boards the tanker, it's hijacked by Russian mercenaries under Revolver Ocelot, who intend to steal the new machine. Two years later still, the offshore cleanup facility called the Big Shell, built on the site, is seized by a terrorist faction styling themselves the Sons of Liberty, and new FOXHOUND operative Raiden is sent to neutralize the threat — though nothing is as it appears. Metal Gear Solid 3: In 1964, CIA agent Naked Snake is dispatched to Tselinoyarsk in the USSR. Backed by Major Zero, Para-Medic, and his former mentor The Boss, he's tasked with rescuing the defecting Soviet scientist Sokolov, secretly developing a nuclear-armed tank, the Shagohod. Snake locates and escorts Sokolov but encounters The Boss, who declares she is defecting to the USSR and hands her new patron, Colonel Volgin, two Davy Crockett nuclear shells. Sokolov is recaptured by the Cobra Unit, Snake is thrown off a bridge by The Boss, and Volgin seizes the Shagohod and detonates one of the shells to cover the theft — blamed on The Boss — while the injured Snake is recovered by fulton extraction. Metal Gear Solid: Peace Walker: Beginning on November 4, 1974, Peace Walker finds Big Boss running his own mercenary unit in Colombia after leaving the United States in the wake of FOXHOUND's formation at the close of Portable Ops. A mysterious paramilitary group, the "Peace Sentinels," lavishly armed with quality weapons, has deployed in Costa Rica, whose constitution forbids an official military, leaving the government powerless against a force with the firepower of a land army — a presence that threatens the balance of power between East and West.