Spinster Miss Dido Kent travels to be by her niece Catherine's side after her fiancé breaks off their engagement and disappears, and decides to investigate the breakup while also looking into the murder of a woman whose body was found on the missing man's family estate.

Miss Dido Kent vacations at a cousin's home and encounters distasteful dealings among Surrey's upper classes in the wake of a neighbor's sudden death, a situation that poses complications to her romance with Mr. William Lomax.

On a visit to the ruins of Madderstone Abbey, Penelope Lambe suffers a bad fall from the ancient stone steps. Before she slips into unconsciousness, Penelope manages to say, 'I saw her - It was her.' The Crockford sisters are sure that what made Penelope fall was that she saw the Grey Nun, the ghost that is reputed to walk the abbey's ruins.