An espionage thriller set in an alternate near future. In a prologue chapter, legendary operative Solid Snake infiltrates a tanker on the Hudson River to photograph evidence of a new Metal Gear walking battle tank, only for Russian mercenaries to hijack the vessel and for his old rival Ocelot to seize the machine and sink the ship. Two years later, Snake is branded a terrorist while an offshore facility called the Big Shell rises to clean the resulting oil spill. When a group calling itself the Sons of Liberty storms the facility during a presidential visit, taking hostages and threatening its destruction, a rookie agent codenamed Raiden is sent in alone to rescue the captives and stop the terrorists. Aided by mysterious allies and haunted by his own past, Raiden uncovers a tangled web of deception reaching far beyond the Big Shell.