In this seventh book of the series, Clive and Henrietta return to England to find Castle Linley in financial ruin. When Clive's cousin, Wallace, invites an estate agent in to assess the home's value, the agent is later found poisoned, throwing all of the Castle's guests into suspicion. Clive and Henrietta are soon drawn into an investigation, which is slowed by an incompetent local inspector and several unexplained phenomena--the cause of which many, especially the frail Lady Linley, believe to be the workings of the ghost of a hanged maid.

Meanwhile, Gunther and Elsie have begun  life on a farm in Omaha. Circumstances are difficult, but they are content--until Oldrich Exely appears, proposing an option Elsie finds difficult to ignore.  Melody Merriweather, still masquerading as a nun to aid Elsie's escape, likewise finds it difficult to ignore a letter with tragic news from home, while Julia, on the other hand, receives a very different sort of letter from Glenn Forbes.

Back in England, Clive is called away to London on suspicious business, leaving Henrietta to carry on with the investigation alone.  When she is mysteriously locked in the study one night, however, things take on a more deadly, supernatural feel, leaving her to fear that  Lady Linley's "ghost" might just be real after all...