True fact: this nasty little 1947 noir was directed by Robert Wise, the same guy who directed The Sound of Music and Star Trek: The Motion Picture. He got around.
Susan Brent (played by Claire Trevor) is in Reno finishing up her quickie divorce. (That was how you worked things back in 1947, kids.) She's staying at Mrs. Kraft's boarding house; she's acquainted with a neighbor, Laury Palmer, who's self-admittedly promiscuous. Laury's going out with Sam Wild, but in order to make him jealous she decides to date someone else.
Bad idea! Unfortunately for Laury, Sam is not only jealous, he's psychotic. Soon there are a couple of corpses, which Susan discovers. Instead of doing the right thing, reporting the find to the police, Susan hops the next train home to San Francisco. But, in one of those Dickensian coincidences, on-the-lam Sam is taking the same train. They strike up a relationship, and…
Well, I've probably already said too much. As film noir goes, this is the real deal, exploring the seedy underbelly of society, where outwardly respectable characters are revealed to have a cold, dark interior. Acting is pretty good. Lawrence Tierney pretty much coasts through the movie with menacing glares and petulant scowls. The story is told with marvelous economy, and the climax is—whoa, didn't see that coming.