During the Vietnam War the U.S. Army brass decides to create a special unit called the Tunnel Rats. Their main mission is to clean-up the Viet-Cong network of tunnels found in the Cu-Chi district outside the South Vietnamese capital of Saigon.The tunnels have become a major nuisance for the U.S. Forces stationed around and inside Saigon. From these tunnels the Viet-Cong can launch devastating and unexpected attacks on any nearby American base as well as on Saigon itself. After the attacks the Viet-Cong forces disappear into the extensive network of tunnels as fast as they appeared, leaving the pursuing Americans empty-handed. The first Tunnel Rats units arrive in the Cu-Chi district in 1968 and they are special-trained to fight hand-to-hand combats underground. They can only rely on a flashlight, a knife and a pistol to try to flush the enemy out. The tunnels, varying in size and length, are booby-trapped with mines and grenades, punji sticks, tripwires, poisonous snakes and enemy snip