The Bastard Queen (The Singer's Legacy)

Beloved bastard of an unloved king, Fiona will do almost anything to please her father, even studying magic though she never shows more than a spark of talent. But the plague that grips their city sends her to work with the dying, as enmity builds between the two peoples her father has brought together. When arson burns a hospital, everyone blames the growing racial tension, until an unexpected suspect comes from the woods on a spirit-quest destined to uncover the secrets of Fiona's past. Then Reynaud, long Fiona's suitor, suddenly asks to marry her sister. Struggling to find a cure for the plague, Fiona becomes ever more convinced that its emergence is no coincidence--and that Reynaud may be leading a conspiracy that will end in genocide.