Heart Readers by Kristine Kathryn Rusch
Approx. 79,590 words.
Published on January 9, 2011 by
Pardu killed his own twin to secure the throne. Now Pardu wants to use magic to decide which of his twins will rule without murder.
The magic calls for heart readers to determine which twin has the pure heart. The team chosen by the palace has a history that makes them unsuitable to choose the next heir.
Or maybe that history makes the heart readers the only ones who know the truth.