The story itself is not exactly profound; it's a lurid potboiler, but Welles adds his unique cinematic touch to make Touch of Evil more interesting. Narcotics inspector Vargas (Charlton Heston) and his new wife (Janet Leigh) have just re-entered his native Mexico for his version of a honeymoon: stay in some tiny border town for a few days, and then go to Mexico City where he is to testify against a drug runner he arrested. The film's first shot, in which the couple stroll the sidewalks while other people enter and exit the border, is one of the great opening shots. A couple of thugs plant a bomb in an unsuspecting vehicle, which slowly crosses the border, stops so the driver can speak to Vargas, and then about ten seconds after it drives off, the car explodes. This entire scene is done in one unbroken take. The explosion forces Vargas to call off the romantic interludes and work on the investigation, and in turn meet up with Hank Quinlan (Welles), clearly the opposite of the straight-shooting Vargas. Hank is a man with few scruples, acting as if he was the law. Unlike Vargas, Hank is impolite, and some would say bigoted. He makes numerous subtle jabs at Mexicans in general, and Vargas and his wife in particular; Vargas because he doesn't 'act' like a Mexican, and the wife for not being Mexican.
During the investigation of what seems like a routine crime of murder, a side issue develops involving Vargas' wife, who is pursue and intimidated by associates of an 'Uncle Joe', the brother of the drug runner. This includes a nasty sequence in which Leigh is alone in a fleapit motel while a bunch of kids (actually working for the brother of the accused drug runner) party it up and make lots of noise. Leigh complains constantly about the noise, but to no avail, and eventually, the kids break in, drug her, and seem prepared to gang-rape her, although the next time we see her, she is in Uncle Joe's territory, still unconscious from the drugs. The attack at the motel is rather intriguing, am I'm curious as to how this scene was presented in 1958. There are a few references to illicit drugs (something which I didn't think the Production Code would have allowed), and there is a rather odd moment when one of the females of the bunch (looking rather butch) offers to view the action.
