A historical YA horror novel based on the infamous real-life inspiration for Countess Dracula

In 17th century Hungary, Anna Darvulia has just begun working as a scullery maid for the young and glamorous Countess Elizabeth Báthory. When Elizabeth takes a liking to Anna, she's vaulted to the dream role of chambermaid, a far cry from the filthy servants' quarters below. She receives wages generous enough to provide for her family, and the Countess begins to groom Anna as her friend and confidante. It's not long before Anna falls completely under the Countess's spell--and the Countess takes full advantage. Isolated from her former friends, family, and fiancé, Anna realizes she's not a friend but a prisoner of the increasingly cruel Elizabeth. Then come the murders, and Anna knows it's only a matter of time before the Blood Countess turns on her, too.