A group of early humans has been lured to the eastern extremes of the North American continent 15,000 years ago. As they settle in their new home, the demands of the once benevolent spirit become more ominous. Too late, their shaman realizes its true nature. The clan is scattered and most are killed when the group tries to resist the demon's will. In the present day, a young engineer and outdoorsman, David Locke, who has spent much of his youth at a family cabin in the Green Mountains of Vermont is familiar with local tribal lore because of his long acquaintance with an old man of Native American descent who lives nearby. Soon after being miraculously spared from certain death in an auto accident, David becomes romantically involved with a young woman, Lori Martin, who he meets during a Sunday outing. However, tragedy begins to strike all around him as close friends and business rivals die. It finally becomes apparent to him that he has become the object of the attention from a supernatural force that is jealously possessive. After Lori is nearly killed, David attempts to convince her that something is wrong. Lori is skeptical and becomes concerned for his emotional state. When he disappears while on a SCUBA excursion, it seems he has been lost forever.