Invasion (Warrior Chronicles #4), Paperback/K. F. Breene

The Hunter wasn't trained to admit defeat. With the title of Chosen secured, Shanti and Cayan must look to the next steps in ripping back their freedom from the most deadly tyrant in the land. Unfortunately, they aren't the only ones with an agenda. Without mental power to defend themselves, the Westwood Lands are trapped within their own walls. Under the threat of torture and eventual death, a new power rises. To be discovered will mean death. But doing nothing is not an option.