The story follows Jerry Welbach as he travels through Mexico to find a valuable antique gun, ''The Mexican'', and smuggle it into the United States. Five years earlier, Welbach had caused a traffic accident in which he hit the car of local mobster Arnold Margolese, who was jailed for five years after the police searched his car following the crash, finding someone tied up in his trunk. In compensation for the jail time, Welbach has been sent on various errands by Margolese's prickly second-in-command, Bernie Nayman. Retrieving the gun will be his final errand. Welbach has a girlfriend, Samantha, with whom he argues constantly and who leaves Jerry prior to the trip over his lack of commitment to their relationship.