Kushiel's Dart (Kushiel's Legacy, Bk. 1)

Phedre no Delaunay was sold into servitude as a child. In the household of an enigmatic nobleman, she is trained in history, theology, politics, foreign languages and the arts of pleasures. Exquisite courtesan, yet talented spy, she may seem an unlikely heroine...but when Phedre stumbles upon a plot threatening her homeland, Terre d; Ange, she has no choice but to act. Betrayed into captivity in the barbarous northland, and accompanied only by a disdainful young warrior-priest, Phedre makes a harrowing escape and an even more harrowing journey, so as to return to her people and deliver them a warning of impending invasion. And that's only the first step in a quest that will take her to the edge of despair and beyond.