After the events of Splinter Cell: Conviction, US president Patricia Caldwell disbands the corrupt Third Echelon and suspends all of its operations.
In its place, the president forms Fourth Echelon with Sam Fisher as it's head - answerable only to Caldwell. The newly formed group are set to travel the globe making sure that all of Third Echelon's activities are halted for good.
Meanwhile, a terrorist group known as the Engineers take a stand against the United States' global military presence. They give the US an ultimatum known as the Blacklist – the US must withdraw their military from around the world, or find their interests subject to a deadly countdown of escalating terror attacks.
It is now up to Sam Fisher and his team to track down the Engineers and stop them by any means necessary, stopping the Blacklist countdown before it reaches zero.
