On July 4th, 2007, a North Korean missile base is hacked and used to launch a Cruise missile against the USS Clarence E. Walsh in the Korea Strait. US Intelligence suspects that the North Koreans were not responsible for the attack, and the US decides to strictly defend against North Korea. While they mass troops to defend Seoul, the Americans also send Third Echelon agent Sam Fisher in North Korea to investigate. At the same time, the Ghosts are deployed behind enemy lines to carry out sabotage, reconnaissance and quick strikes against the NKA should the conflict explode. Officially, not a single US asset is in North Korea.