The book is very impressive. Well written, wonderful descriptions, unusual in the way it mixes the scary possible ghost story, possible murder, family dynamics, and mystery. But I found it too stressful. It's a personal problem that I have with some books.
I always include major spoilers (hidden), to help with my memory issues. Read them at your peril!
Imogen, third wife of an eminent professor, has been widowed, and it's not clear how grief stricken she is.There is certainly an ambivalence towards her far from faultless husband sometimes. Her acerbic thoughts, whilst saying all the right widowy things, are funny. Someone phones in the middle of the night to accuse her of murder. Then his family start to descend on her, and seem to be intent on staying put, for no clear reason. Odd things start happening, which make Imogen wonder if the house is haunted.