To honor the weekend of Lebowski, give me your favorite mysteries (books/movies) that start in someone's big fancy house

Watching Lebowski last night, I realized I must have read a dozen novels of this basic structure. The debt to Chandler is real.

I've been taking in the discourse on Lebowski, including the featurette with the Coens on the Blu-Ray. Chandler comes up over and over again but Lebowski really reminds me of Ross Macdonald almost as much. I'm a big fan of Ross Macdonald (The Galton Case is the one to start with IMO). One of my favorite Paul Newman movies is Harper, and that's also based on a Ross Macdonald story. In Harper, Newman toddles around LA in a groovy sportscar and gets mixed up with a bunch of different women, gets into fights, almost gets arrested etc.

Anyway, we know the drill: a private eye (usually) is summoned to a big fancy house and someone there explains that a person has gone missing, a fee is negotiated and the case begins. In the Coens featurette, Joel used the word "episodic" and it's so true, It is essential that you could just endlessly add scenes with new people to meet like beads on a bracelet. You can always add some new environment to figure out.

But in the end, it has to return to the big fancy house and the rot that resides within.

Anyway, what movies and books do you like that do this?