chunk: The secret of the title is the parentage of the heroine, Rosamund Treverton, who has been passed off as the daughter of the wealthy former actress Mrs Treverton of Porthgenna Tower, but is in fact the illegitimate child of her servant Sarah Leeson by a local miner (Mrs Trevertonâs motive was to provide her husband with a child, being apparently unable to bear children herself). Sarah writes down the details of the secret from the words of the dying Mrs Treverton, and hides the paper bearing the message in an unused room at Porthgenna.