Erzsébet Báthory, whose infamous place in history characterises her as the 'Blood Countess', is rumoured to have murdered 600 peasant girls. The Nightingale's Castle tells the gripping story of an intelligent and capable woman fighting to hold onto her wealth and independence, in a world where the poor and the wealthy alike face savage challenges.

In 1573, Countess Erzsébet Báthory gave birth to an illegitimate child. The infant, a girl, was swiftly bundled up and handed to a local peasant family to be brought up in one of the hamlets surrounding the Castle. Many years later, 15-year-old Boróka reluctantly leaves the safety of the only home she has ever known in the foothills of the Carpathian Mountains. Trusted members of the Countess's household have been sent out to gather new serving girls, and the kindly old man who has taken care of Boróka for almost all her life knows that it is too dangerous to turn them away.

Boróka struggles to find her place at Cachtice Castle: she is frightened of the Countess's reputation as an alleged murderer of young girls, and the women who run the castle are terrifyingly cruel. When plague comes into the heart of the castle, a tentative bond begins to form between Boróka and the Countess Báthory. But powerful forces are moving against the Countess whose wealth poses such a threat to the King: can the Countess really trust the women who are so close to her? And when the show trial begins against the infamous 'blood countess' where will Boróka's loyalties lie?