Village herbalist Rose accepts a generous purse of gold to treat Duke Alexander at the grim Thornwood Castle, where rumour says every healer sent there dies soon after arrival. Rose finds slowacting aconite poison in the duke’s nightly tonic, proving the famed family curse is premeditated murder. She confronts scheming steward Gideon, who accuses her of witchcraft to silence her. Doubtful yet trusting, Alexander lets Rose treat him with herbs. Coerced housekeeper Elara warns Rose secretly. Jealous Lady Vivian arrives to claim her old betrothal to Alexander. Allying with Gideon, she plants poison to frame Rose for witchcraft. Imprisoned, Rose receives Elara’s smuggled letters from late fiancée Eleanor, exposing Vivian poisoned her to cover up a royal crime.
