That evening, just before the party begins, there's a train accident on a nearby line and the survivors are re-routed to Sterne until the railway can bus them on their way. The family are a fairly self-involved lot and don't cope very well with having to do the right thing towards fellow human beings. Especially when the survivors bring with them someone from their mother's disreputable past who shows the family the cruelty hiding in their shallow selves.
The book was well-written, but not to my taste. I found the storyline and characters repugnant. I know that it is very easy for people to behave that badly as long as the majority are in agreement - it's how mobs turn into mass-murderers. But, I don't want to read about it. The synopsis made me believe it was a ghost story, which it is. A ghost story with a fairly severe look at how wicked and heartless humans can be.
