Prudence Smith, one of Jane's former servants, is dead of an apparent suicide. But Lenox suspects something far more sinister: murder, by a rare and deadly poison. The grand house where the girl worked is full of suspects, and though Prue had dabbled with the hearts of more than a few men, Lenox is baffled by the motive for the girl's death.
When another body turns up during the London season's most fashionable ball, Lenox must untangle a web of loyalties and animosities. Was it jealousy that killed Prudence Smith? Or was it something else entirely? And can Lenox find the answer before the killer strikes again - this time, disturbingly close to home?