This hokey-jokey comic thriller doesn't add up to the proverbial hill o' beans, but it's an engaging curio all the same. Pitt is Jerry, American to the bone. The titular Mexican is actually a handwrought antique pistol. Jerry's mobster pals insist he stand up his girlfriend, Samantha (Roberts), head South of the Border, pick up the gun and bring it back home. Straightforward enough if Jerry wasn't such a loser. Meanwhile a hitman has kidnapped Sam as a little extra distraction. That the killer in question is played by Gandolfini suggests how loaded with stars the movie is. That might be a problem if audiences expect Brad and Julia to share 'quality time'; in fact they're apart for most of the film, and bickering when they're together. Gandolfini packs more emotional baggage. Screenwriter JH Wyman keeps the parallel storylines buzzing with smart dramatic zigzags and self-consciously tangy dialogue, but the whole thing gets a bit mired down with extraneous flashbacks. Director Verbinsky means to show you a good time, and he does, even if he sometimes he gets carried away.