Tom Clancy's SSN is a simulation of the 688i (Improved Los Angeles-class nuclear hunter/killer submarine). The game player is in command of USS Cheyenne (SSN-773) in a limited war against China over the Spratly Islands. Gameplay is limited to a 15 mission single-player campaign in which the player carries out anti-submarine, anti-surface ship roles, intelligence gathering activities, and the launch of submarine based cruise missiles. Tom Clancy also wrote a book by the same name, based on this storyline.