A mild-mannered electronics salesman embarks on a seemingly mundane journey across the Californian desert to meet a client. His drive takes a dark turn when he overtakes a grimy, dilapidated tanker truck. What begins as a simple maneuver on the highway quickly escalates into a life-threatening pursuit. The faceless truck driver proves to be a relentless and mysterious antagonist, taking the salesman's casual pass on the road as a personal offense. As the journey continues, the salesman’s initial irritation gives way to confusion and fear as the truck begins to follow and torment him without any clear motive or provocation.

Seeking help at various points along the way – gas stations, roadside diners, and even from a passing train – the salesman tries desperately to shake his pursuer. Each attempt at escape or assistance turns futile as the truck driver manipulates situations, using his menacing vehicle as both a weapon and an instrument of terror. Through nerve-racking chases and strategic evasion, the salesman's wits and will to survive are put to the ultimate test. His isolated struggle on the road becomes a primal fight for survival, against a seemingly unstoppable and faceless adversary encapsulated within the roaring engine of the tanker truck.