Clwyd Castle by Jayne Bamber

Elizabeth Bennet and Fitzwilliam Darcy are trapped in a castle with twenty other Austen characters… and the bodies are starting to pile up….

Elizabeth Bennet is asked to accompany Sir Edward Gardiner on a journey to Wales, though he has been vague in explaining their purpose. When she arrives at Clwyd Castle, she meets new friends and an old nemesis, as well as many new companions just as secretive as Sir Edward.
When their charming host announces his plan to free his guests from the burden of blackmail at his father’s hands, good intentions quickly lead to an increasingly grim situation – and then the murders begin.
Elizabeth must decide who to trust, and Mr. Darcy quickly proves to be amongst the few people she can rely on when the castle is locked down and the murderer strikes again. And again.
Alliances form and allegiances are tested, and Elizabeth, Mr. Darcy, and those they trust are forced to take matters into their own hands, putting their lives at risk to expose the truth in the nick of time.