Trust is a delicate thing, and no one knows that better than Rosalind Thorne. Lady Melbourne has entrusted her with recovering a packet of highly sensitive private letters stolen from her desk. The contents of these letters hold great interest for the famous poet Lord Byron, who had carried on a notorious public affair with Lady Melbourne's daughter-in-law, the inconveniently unstable Lady Caroline Lamb. Rosalind is to take up residence in Melbourne House, posing as Lady Melbourne's confidential secretary. There, she must discover the thief and regain possession of the letters before any further scandal erupts.

However, Lady Melbourne omits a crucial detail. Rosalind learns from the Bow Street runner, Adam Harkness, that an unidentified woman was found dead in the courtyard of Melbourne House. The coroner has determined she was poisoned. Adam urges Rosalind to use her new position in the household to help solve the murder. As she begins to untangle a web of secrets and blackmail, Rosalind finds she must risk her own life to bring the desperate business to an end . . .