La Reina Roja, Paperback

Set in an imaginary kingdom, this novel presents a society divided by blood color--commoners have red blood, while those with silver blood form an elite class with supernatural abilities. Mare, a member of the red-blooded class, is one day noticed by the king for her special powers and absorbed into the life of the court. However, what they don't know is that she's an agent for the Scarlet Guard, who is in the midst of preparing a rebellion.