The Rebel and the Captive by Kris K. Haines

Sparks of rebellion can catch fire, even in the darkest hour.
Cassandra Fortin has been taken by her enemies, locked away at the edge of the world and separated from everyone she loves. But when a chance encounter offers her the opportunity to fight for her life, she seizes it despite insurmountable odds. She’ll need every ounce of her new strength, not to mention her new friends and evolving power, to win the day—and her freedom.
Tristan Saros has been taken by his allies, spirited away to an ancient jungle village where a group of rebels have been preparing for their Prince’s arrival for centuries. Their goal? Restore Tristan to the Crystal Throne of Ethyrios and end the reign of his terrible brother. There’s only one problem: he may have to forsake Cassandra to do it. As Tristan grapples with his new fate, dodging threats from all sides, he’ll have to make an impossible choice—save his people or save the woman he loves.
But if the Rebel and the Captive can find their way back to one another? Sparks ignite and worlds will burn.