David Janssen, as Jake, and Keenan Wynn, as his partner and pal Donny, are independent truckers who are hired along with their big rig by a man named Kleiner (William Schallert) to haul an unknown cargo from Los Angeles to Houston for a handsome stipend of $6000, but with a deadline to be met for their labours. Kleiner is apparently a front man for a corporation dealing in government contracts, and the only description he will offer the driving duo of their sealed cargo is that it is "non-explosive and non-chemical", sweetening the payoff with a guarantee that Jake's driving license, temporarily reactivated for this assignment, will be permanently reinstated upon its timely completion, having been suspended after he punched an officer at a weighing station outlet. Success of the journey quickly becomes in doubt, as the 18 wheeler is harried by a persistent group of men with homicidal tendencies who obviously are covetous of the van contents and who must be continually fought off by Jake and Donny as their pursuers, little heeding the rules of the road, employ automatic weapons and a helicopter in their highjacking attempts. When not warding off sallies from the stalkers, Jake finds time for the obligatory romantic interlude, his paramour being a young woman (Lee Purcell) living with her grandfather in a highway bypassed hamlet, and their entr'acte, although handled with taste, makes little sense unless one accepts that some sort of intermission is called for by the cargo hunters. Even less rational is the climactic conflict between the two buddies and their violence-prone adversaries, but the film's ending includes a nicely ironic twist and the relationship between the two friends, although skimpily developed, is the best part of the scenario, since Donny has a heart "condition" and Jake's concern for him is made convincing by Janssen.
