The Sundial - Shirley Jackson

Mrs Halloran has inherited the great Halloran house on the death of her son, much to the disgust of her daughter-in-law, the delight of her wicked granddaughter and the confusion of the rest of the household. But when the original owner - long dead - arrives to announce the world is ending and only the house and its occupants will be saved, they find themselves in a nightmare of strange marble statues, mysterious house guests and the beautiful, unsettling Halloran sundial which seems to be at the centre of it all.