After spending the better part of a decade in self-imposed exile, Orson Welles found himself back in Hollywood in the late '50s, which is when he made his final studio film, the late-period noir Touch of Evil, for Universal. Originally only contracted to act in the film, Welles was brought on as writer and director at the insistence of star Charlton Heston, who apparently wasn't too bothered by the fact that he was plainly miscast as a Mexican narcotics agent. As for Welles, he gave himself a plum role as a perpetually disheveled border-town police captain so steeped in corruption that he winds up at odds with the upstanding Heston, who happens to be on the scene (with his newly minted wife Janet Leigh) when a car bomb goes off just inside Welles's jurisdiction. This, incidentally, happens at the very end of the justly famous tracking shot that opens the film, a brilliantly choreographed sequence that reminds viewers why Welles was -- and is -- considered a genius.
Heston's first instinct is to protect Leigh, but his involvement in the case (which develops more and more wrinkles the longer he's on it) keeps them apart, leaving her vulnerable just when he's being targeted by the family of a man he's getting ready to testify against. This also leaves the door open for Welles to introduce such larger-than-life characters as Akim Tamiroff's string-pulling schemer and Dennis Weaver's oddball motel night man, as well as Mercedes McCambridge in an unbilled cameo as one of the gang members that terrorizes Leigh in Heston's absence. (Joseph Cotten also gets a blink-and-you'll-miss-him cameo early on as the coroner who heralds Welles's arrival on the scene.) Meanwhile, Heston comes to believe that Welles isn't completely on the up-and-up, which puts him at odds with police sergeant Joseph Calleia but gains him an unlikely ally in district attorney Mort Mills (best known for playing the intimidating motorcycle cop in Psycho). And Marlene Dietrich pops up as the proprietress of a house of prostitution Welles patronizes after hours. She isn't given a whole lot to do, but she does get the closing line, which succinctly sums up Welles's character: "He was some kind of a man. What does it matter what you say about people?"