Above the Arctic Circle, in the National Wildlife Refuge, Geologists Mike and Christine Barnes, have been preparing subterranean maps of the strata beneath the coastal plain. Along with their two assistants and another couple, friends who are wildlife photographers, they experience the shock wave of a nearby impact to the earth's surface which they believe to be a meteor. Isolated from the outside world by an early winter storm, they prepare to investigate the following morning. Joined by three Rangers from NORAD who are accompanied by a scientist and his assistant from SETI, they travel together to the impact site. NORAD believes it to be a foreign aircraft shot down over Alaskan skies. SETI believes it is a UFO. What they find involves them in a life and death struggle with an enemy who knows no human boundaries.