Set in 1905, the film follows the exploits of the likable but raffish Boon Hoggenbeck (Steve McQueen), who takes an interest in a new car, a new 1905 Winton Flyer that is the property of a man named Boss (Will Geer), the patriarch of the McCaslin family, who live in the Mississippi area where Boon lives. When the taking of the car first by Boon and then by Ned (Rupert Crosse) (they show themselves to be reivers, or thieves, in the film’s start, hence the title) leads to a public brawl, the local magistrate lets them off by a bond that Boss pays on the condition both men stay out of trouble and far away from the car while he is away with family to attend a funeral. That is soon changed by Boon, who takes the car again to go up to Memphis to see his woman Corrie (Sharon Farrell) and talks his young friend Lucius (Mitch Vogel) into going for the ride. Ned stows away as well, but Boon grudgingly allows him to come. Other characters include a horse that loves sardines and races for them, a friendly bordello madam and her amiable employees, and a man with a horse who lives near an impassable sinkhole full of mud for which he charges expensive rates to get both carts and cars through.