David Mann (Dennis Weaver), a mild mannered electronics salesman, is driving cross-country on a two-lane highway when he encounters an old oil tanker driven by an unseen driver who seems to enjoy annoying him with dangerous antics on the road. Unable to escape the demonic big rig, David finds himself in a dangerous game of cat and mouse with the monstrous truck. When the pursuit escalates to deadly levels, David must summon his inner warrior and turn the tables on his tormentor.