Set in 2014, five years after the "Manhattan Incident" (the events of the Plant chapter from Metal Gear Solid 2), Metal Gear Solid 4 portrays a world where the restriction of military intervention on foreign soil has been eased, fueling the need for private military companies (PMCs) to fight proxy wars for business purposes. Nanotechnology has become prominent, both to enhance the capabilities and enforce the loyalty of mercenaries. The five largest of these PMCs are owned by a single mother company named Outer Haven, which is operated by Liquid Ocelot. Amassing an army whose manpower rivals that of the United States, Liquid prepares to launch an armed insurrection. With the world once again in crisis, a rapidly aging and disillusioned Solid Snake is deployed into the Middle East by Roy Campbell to terminate Liquid.