The Winner's Curse by Marie Rutkoski
Kestrel is the only daughter of a demanding General in the Valorian military, which allows her many privileges and luxuries. But it does not release her from the requirement that all Valorian women have and that is to either marry or join the military. The General would like her to join the military, but Kestrel is not sure that is what she wants for her future.
Kestrel has never purchased a slave before, but when she sees Arin on the auction block, she finds herself bidding, an action she cannot explain. Her father is in need of a smith and so there seems to be some justification for bringing the new slave home. As Arin takes on the task of making horseshoes and swords in his new home, he and Kestrel develop a friendship of sorts. But all is not as it seems and soon they find themselves fighting for their lives.
Rutkoski creates a world that is believable with characters that draw you in and have you rooting for them right from the beginning. This was a fun read that has me looking forward to the next book in the series.