The Big Sleep (1946)
Very glad I read the book of this recently because it’s very - famously - convoluted. At least Marlowe always seems to know what’s going on, in contrast to the Elliot Gould Marlowe from The Long Goodbye. They changed some bits and pieces for the movie, but as far as I can tell there are three crime scenarios that overlap in various ways.
One: The entrypoint. A rare book dealer named Geiger is blackmailing a rich guy’s (Sternwood) wayward daughter (Carmen), but then he’s killed and the daughter is found drugged out at the scene. A photo was taken that places her there but it is stolen by someone. This someone is Sternwood’s chauffeur who was in love with Carmen, but he is killed and the photo stolen which brings us to…
Two: A guy named Joe Brody, who works for a casino guy named Eddie Mars, who was staking out Geiger’s house at the same time for… reasons I forget right now, but anyway ended up with the picture. Brody uses the picture to also blackmail Carmen. Marlowe basically figures all this out and gets the picture back and we’re done except for…
Three: While all this was happening, everyone is asking Marlowe if he’s investigating the disappearance of a guy named Regan who ostensibly ran off with Eddie Mars’ wife. He is not investigating this, until he is, and it turns out Carmen is a psycho who killed Regan and has been protected by her sister Vivian the whole time.
I had to refer to several sources to get all that straight (and even then it’s not fully) but it’s a very vibes-based movie, I should mention that Marlowe is Humphrey Bogart and Vivian is Lauren Bacall (something like 19 at the time) and the two had an affair during filming and were married by the time it came out. Special notice goes to a scene where Marlowe is staking out a shop by hiding in the book store across the street and the girl working there all but hurls herself at him.