We have Always Lived in the Castle

Some time back, some person put arsenic in the sugar bowl at dinner and now the whole family is dead except for Uncle Julian, an invalid, who eats very little sugar; Constance, who eats no sugar; and Mary Katherine (aka Merricat), who was sent to her room without supper for misbehaving that fateful night. Constance was the one who was tried for the multiple murders, but she was not convicted. Now the three of them continue to live in the family home, shut away from the resentful and mean-spirited villagers except for Merricat's twice weekly trip to the grocery store. The other wealthy families--for they had money and live in a mansion--occasionally come to call, but otherwise, they are totally isolated. When Cousin Charles shows up, the balance--such as it is--is upset and things begin to go quickly awry. A fire is started by someone in the house, then the fire department puts it out. But the villagers take the opportunity to rampage through the house breaking everything they find. Uncle Julian dies of a heart attack in the melee. Only Constance and Merricat are left. What are they to do?  One of the survivors is the poisoner, but the two nevertheless vow to go on. A totally strange book by Shirley Jackson, who also wrote The Haunting of Hill House. Apparently this has also been performed on stage.