As I mentioned in Fun Settings for a Murder Mystery, murder at a dinner party held in a mansion is one of the most iconic golden-age settings for a murder mystery. It’s so iconic that the (sort of) murder mystery board game Clue (or Cluedo, if you’re British) has exactly this setting. It was necessary, but fitting, that the movie Clue had it as well. Parodies must be instantly recognizable.
There may not be a more recognizable setting for a murder mystery. And yet, I can’t actually think of them being done very often in golden age mysteries.
I cannot think of any Sherlock Holmes stories like this, though a few came close. Of all of the Lord Peter Wimsey novels, only Clouds of Witness comes close, though that was a rented hunting lodge, not a mansion, and there was no dinner party and the murder happened in the middle of the night. I’m sure that there was at least one Poirot with this. A quick search turns up Murder in Three Acts, which has more than one poisoning at a dinner party. As I’ve mentioned, Murder on The Orient Express is similar in structure to a dinner party at a mansion, though it is, of course, a train and not a mansion. I can think of a Miles Bredon case, The Body in the Silo, which is a fairly classic example of it. I can’t think of any Father Brown stories with this setting. I’ve only read two Dr. Thorndyke stories, so I can’t speak with any authority on them. I find the dinner party plot unlikely in a Dr. Thorndyke story unlikely, though, and a quick search doesn’t turn anything up.
To be fair, I suspect that murder at a dinner party is likely to have been the plot of plays more often than of novels. They’re a fun and interesting setting for a novel, but they have a much greater benefit to a play: they put everyone into very few settings that don’t need to be changed out. As I discussed in Were Plays the TV of Previous Centuries? most of these were lost.
So, why is this setting, despite being so richly suggestive and iconic, so (relatively) uncommon in novels?
I think that the answer is that it’s hard to pull off. Especially if the murderer does not use poison, getting time alone with the victim in order to do away with him is not easy in the context of a dinner party, with cigars, billiards, tea, etc. following. The timing is tight, and that is not easy to manage with many people going about the activities of a party, even a low-key party. This is not merely a problem for the writer; it is also a problem for the murderer. There must be some reason, then, why the murderer would wait for such a difficult time to commit his murder, and moreover one that undeniably puts him, if not at the scene of the crime, at the most a room or two over from it.
Novels, being so much longer than either short stories or plays, give the reader time to think about the story. They spend time with all of the characters in a way that they don’t in a play or short story (or movie, though those are less common). The audience to a play will forgive a playwright for taking liberties with a story that are necessary to fit the story onto a stage. The reader of a novel is not nearly so forgiving because the writer of a novel does not need to take liberties to fit a story into a book.
I think that the rock upon which this setting falters, in novels, is plausibility from the murderer’s perspective. At a dinner party in a mansion is an absolutely terrible place to murder someone. All of the things which make it interesting also make it a bad plan. This can be made to work by springing the need for the murder upon the murderer—a sudden realization that he has mere minutes to silence the victim before he is ruined, for example. This is a workable condition, but a limiting one.
Another possible way of working around it is for the murderer to have as part of his plan the framing of someone. He might be killing two birds with one stone, as it were—killing the one and getting the other out of the way through a conviction for murder. That said, this was a better plot back in the golden age of mysteries, in England, where execution was common and swift. In the modern US, where execution is rare and often takes decades, the amount accomplished by framing someone for murder is less. Not nothing, though. It could effectively get a love-rival out of the way, or open up a coveted job.
In summation, I think that this is an under-used setting, which can be made greater use of, and should.