A team of commandos, led by Dutch Schaeffer (Arnold Schwarzenegger), go on a mission to rescue captured airmen from terrorists. When they discover that the airmen have been slaughtered beyond recognition, the team decimates the enemy encampment. Before they can radio for a lift-off, an invisible alien specie begins to kill the team members. Hunted like animals by an enemy they cannot see, the team must survive in the jungle before they are all killed.