As Liberation Day had ended, a spectacular sunset of huge, towering, cream-white cumulonimbus edged with gold, the men of the American Second Infantry Division Platoon manning OP (Observation Post) Fort Dyer were at “stand to,” normal procedure at sundown all along the DMZ and a drill that was as old as the Roman legions, as soldiers stood armed, silent, straining to hear or spot any movement in the rich green valley of rice paddies below that was turning soft black in the dying light.
Sgt. Elmer Franks, standing on the trench’s wooden duck-boards, was looking through the periscope binoculars. He could see nothing beyond the wire. Soon he would move over to the big infrared scope; no color in the picture, but contrasting black and white shapes were enough. The problem with the infrared scope, however, was that it was not passive, so that rather than simply picking up infrared emitted by a target, it needed to project an infrared beam, which in turn could be picked up by the other side — if they had the right equipment. To cover their bets, the Americans at Fort Dyer also had a “TI,” or thermal imager, which was passive and through which radiant heat from beyond the wire would show up in opaque sections, like white blobs on an X-ray film.
Overhead storm clouds began crashing into each other, lightning spitting in the distance. Franks looked through the TI.