Regular guy Jim Halsey is driving a Cadillac across Texas to San Diego. To stay awake, he picks up a fellow traveler on the road, who introduces himself as John Ryder. But he turns out to be a cunning sadistic maniac who has turned Jim’s life into a nightmare. Killing everyone on Jim’s way, Ryder sets up the poor guy, and soon he is chased not only by the maniac, but also by the entire state police.
All attempts to find help fail, and, as a result, even Jim’s new girlfriend Nash does not believe in the existence of a mysterious killer. It remains only to hope for themselves and take up the challenge of the Companion…