First off, this is a play.
I've read maybe one other play in the last 15 years, and so I was a bit taken aback when I opened the tiny novella. But this text was well worth the effort!
We follow a family bereaving their departed father, so an adult daughter (logical and responsible scientist), an adult son (a libertine; aimless, romantic and depressed), and their aunt, and the conversations leading directly up to the reading of the patriarch's will. Many conversations have to do with mental distress, and also heredity and evolution.
Other characters include a doctor, a young lawyer, and some funny side characters like the servants.
I would describe this as a gothic satire that everyone interested in the genre should try... The social commentary is on point!