Fans of Horror Films and Novels

Shirley Jackson's Haunting of Hill House is phenomenal.

If you haven't read it, I recommend it. But it's understated and more psychological - but she handles tone and atmosphere in an understated way that is terrific and chilling. You could check out "The Lottery" as a short story to see if you dig her style before committing to an entire novel

but when you say "well written" it was the first title that jumped to mind - she's an absolutely terrific writer

edit: and the ending....!