"January 31, 1968. The Tet Offensive has just begun. This massive, multi-pronged assault involved NVA units and guerilla fighters attacking targets throughout South Vietnam. Major cities such as Hue and Saigon were hit hard by the Viet Cong, catching the American defenders totally off guard. In preparation for the offensive, the VC have tunneled into the Saigon sewer system, and are using it to move troops into the city. If they control the sewers, the VC will have direct access to the Presidential Palace. The American troops must work to keep the VC from crossing the bridge into the city, but they must also be wary of attacks coming from underground if they hope to keep Saigon."