What is the story behind Metal Gear Solid 2

Boat Chapter (first half): Snake go's on to a boat to find the new Metal Gear Being devloped and to stop the terrorist's who call them selves the "Son's Of Liberty" Plant Chapter (Second Half): It's 2009 and there is a report of Solid Snake helping the Son's Of Liberty launch the new Metal Gear so Foxhound sends Raiden (Jack) to find out. And then he meets a person (who is Snake but Raiden doesn't know).