Synopsis according to Goodreads:
“It is 1803, six years since Elizabeth and Darcy embarked on their life together at Pemberley, Darcy’s magnificent estate. Their peaceful, orderly world seems almost unassailable. Elizabeth has found her footing as the chatelaine of the great house. They have two fine sons, Fitzwilliam and Charles. Elizabeth’s sister Jane and her husband, Bingley, live nearby; her father visits often; there is optimistic talk about the prospects of marriage for Darcy’s sister Georgiana. And preparations are under way for their much-anticipated annual autumn ball.Then, on the eve of the ball, the patrician idyll is shattered. A coach careens up the drive carrying Lydia, Elizabeth’s disgraced sister, who with her husband, the very dubious Wickham, has been banned from Pemberley. She stumbles out of the carriage, hysterical, shrieking that Wickham has been murdered. With shocking suddenness, Pemberley is plunged into a frightening mystery.