"The Haunted Hotel: A Mystery of Modern Venice" is a thrilling novel by Wilkie Collins. It tells the story of Lord Montbarry who breaks off his engagement to Agnes to marry another woman, and later dies under mysterious circumstances in a hotel in Venice. The hotel is believed to be haunted and the mystery deepens as strange occurrences unfold within its walls. The novel is a captivating blend of horror and suspense, as it seeks to reveal Lord Montbarry's true fate.