The Mexican is a 2001 movie by director Gore Verbinski starring Brad Pitt and Julia Roberts, with a plot that is a somewhat unusual mixture between romantic comedy and road movie.

The script was originally intended to be filmed as an independent production without major motion picture stars, but Roberts and Pitt, who had for some time been looking for a project they could do together, learned about it and decided to make it. Therefore the movie was then advertised, somewhat misleadingly, as a typical romantic comedy star vehicle. Because the script does not focus on the Pitt/Roberts relationship extensively and because the two share relatively little screen time together, many viewers felt somewhat let down by the movie.

The plot is about Jerry Welbach's (Pitt) trials and tribulations as he tries to get a famous antique gun, The Mexican, out of Mexico and into the United States. Five years earlier he had caused a traffic accident in which he hit the car of local mobster Arnold Margolese (Gene Hackman), who then had to go to jail for five years when the police searched his car after the crash. As a compensation for the jail time, Jerry is sent on various errands by Margolese's second-in-command, Bernie Nayman (Bob Balaban).

Quickly it becomes pretty clear to Jerry that this, his final assignment by Margolese, will be difficult, as the gun seems to carry a curse. The various tellings of the history of the gun and the cause of the curse are a running joke throughout the movie, but suffice it to say that present and past get more and more similar in each telling of the story.

Jerry's girlfriend Samantha (Roberts), with whom he was undergoing marital counseling, even though the two are not even married yet, is kidnapped by "Leroy" (James Gandolfini) after he apparently kills a black hitman who seems to have been trying to abduct or kill Samantha. "Leroy" however assures Samantha that everything will be fine if he is handed the gun for Margolese by Jerry.

Meanwhile, Jerry is able to locate the gun, which had been stolen from him, but also has to outwit his friend Ted (J. K. Simmons), who has been instructed to kill Jerry if necessary.

Samantha and "Leroy" drive to Las Vegas, hoping for the return of Jerry. On the ride, "Leroy" admits that he is gay, much to the amusement of Samantha, who thinks this is strange considering his occupation. The two exchange some relationship advice and pick up Frank (Michael Ceveris) at a diner, who is clearly sexually interested in "Leroy". Frank and "Leroy" spend the night together, and the next morning Samantha encounters a pensive and changed "Leroy". When she asks him about the tattoo on his arm, which says "Winston", he replies that Winston is someone he does not like anymore.

After "Leroy" and Samantha have gone out for breakfast, the black hitman appears again, killing Frank. As it turns out, he is wearing a bulletproof vest and was therefore able to survice the earlier shooting by "Leroy". When the killer returns when "Leroy" and Samantha have come back, he is killed by "Leroy" in revenge for his slaying of Frank.

Unfortunately, Jerry has lost his passport and cannot leave Mexico, therefore "Leroy" and Samantha have to fly there. When Jerry sees "Leroy", he gets suspicious, since he had met the real Leroy earlier and recalls he is black. "Leroy" however finds out that Jerry is on to him and knows that he has to kill him now. But in the last minute he prefers to be killed himself by Jerry, in accordance with something he said to Samantha earlier about death and love. When "Leroy" is dead, Jerry looks in his passport and finds his real name is Winston Baldry.

The resolution to the plot is that the real Leroy was hired by Margolese, while Baldry was hired by Nayman, who wants the gun for himself. In a final confrontation, Samantha kills Nayman with The Mexican, undoing the curse. The gun is then given to a relative of the gunsmith who made the gun long ago by Margolese, who had learned about the whole story about the gun while in prison because of the accident caused by Jerry.