Entrecroisées mais indépendantes, l'histoire d'une famille réunie pour l'enterrement d'un de ses jeunes membres, tué sur la route, et l'histoire d'un Algérien qui émigre en France et qui raconte dans une lettre à sa fille l'histoire biblique de Jonas.
The movie first starts out with FBI and ATF agents on a pursuit to stop a truck carrying illegal guns as part of an illegal arms operation. The result is the death of the driver, which leads to a disagreement with FBI and ATF agents on involvement with the case.
When David (Lochlyn Munro), a comedian, gets a three night gig at a trucker's bar, his girlfriend, Sylvia (Kristin Davis), leaves him and accepts a ride from a trucker, Jack (Meat Loaf).
While driving cross-country from Boston to San Diego in their new Jeep Grand Cherokee, Jeff Taylor and his wife Amy narrowly miss colliding with a beat-up Ford F-150 that darts in front of them from a connecting road on a deserted highway. Later, while stopped at a gas station, the truck's driver, Earl, exchanges hostile words with Jeff before the couple resume their journey. Shortly afterwards, their Jeep breaks down in the middle of the desert. Leaving Jeff with the car, Amy accepts a ride from a passing big rig trucker named Red Barr driving a Peterbilt 385, to get to a nearby diner and call for help. Jeff eventually discovers that the Jeep's battery connections have been suspiciously tampered with, and, after reconnecting them, drives to the diner, only to discover that no one has seen his wife. When he catches up to Barr on the road and forces him to stop, the trucker claims he has never seen Jeff or his wife before. Jeff hails a passing sheriff, named Boyd, but a brief search of Barr's truck yields no sign of Amy, and he is let go.
Une compétition entre compagnies de transport par camions va être exacerbée lorsqu'il va s'agir de transporter des pièces d'avion en Californie à temps pour embarquer pour le Japon.
Dans un endroit du sud marocain et du Sahara espagnol à l'approche des années 1960, Castagliano qui est un patron aux méthodes douteuses et surnommé « la Betterave » à cause de son diabète, dirige d'une main de fer une entreprise de transport routier dont il exploite les employés. Il engage John Steiner, un routier « mexicain » soi-disant né à Saltillo pour conduire sur 2 000 km vers le sud un véhicule articulé Berliet rouge flambant neuf, affrété d'un mystérieux chargement d'une valeur déclarée de 100 000 dollars, direction Moussorah. Pendant une conversation téléphonique entre Castagliano et son client, on apprend qu'il a engagé Steiner la veille pour qu'il en sache le moins possible sur ce camion.
Dyan Cannon plays Madie Levrington, a wealthy woman who is also neurotic. She was committed to a New York mental institution by her husband, Benjamin, in order to keep her from divorcing him and taking his money. She manages to escape and, in the process, hitches a ride on a livestock truck.
Wealthy Texan Big Enos Burdette (Pat McCormick) and his son Little Enos (Paul Williams) seek a truck driver willing to bootleg Coors beer to Georgia for their refreshment. At the time, Coors was regarded as one of the finest beers in the United States, but it could not be sold legally east of the Mississippi River. Truck drivers who had taken the bet previously had been caught and arrested by "Smokey" (CB slang for highway patrol officers, referring to the Smokey Bear–type hats worn in some states).
As is the case with the two preceding Smokey and the Bandit films, Smokey and the Bandit Part 3 begins with Big Enos (Pat McCormick) and Little Enos (Paul Williams) offering a sizable wager on one's ability to transport a shipment a large distance in a short period of time. Offering a slight twist, however, the offer is this time made to a retiring Sheriff Buford T. Justice (Jackie Gleason), betting $250,000 against his badge on his ability to transport a large stuffed fish from an eatery in Florida to Texas.