Lost Kingdom by Laurel Black

Trusting him is the only way to save the kingdom.
Betraying her is the only way to keep them both alive.
Stripped of her memories and her magic, Raven has been left for dead.
As a prisoner in the enemy’s mineral mines, her only clue to who she is and where she came from is the mysterious map tattooed on her hand—a map containing hidden secrets that some people would kill for.
Jeddak is one of those people.

A warrior from the Kovak tribe, he’s hunting for the powerful Zavien stone to pay the corrupt king’s ransom. If he doesn’t return home with it by the new moon, his betrothed will be executed.
When Jeddak discovers that a prisoner named Raven has the only map that leads to the artifact, he allies with her as they navigate treacherous lands and battle against ancient magical forces to unravel the map’s secrets. But can Raven trust this stranger who’s helping her? If the map gets into the wrong hands, thousands of people will die.
As their feelings for each other grow, their tenuous alliance begins to fray. Until Jeddak is forced to make a decision—betray Raven or forsake his kingdom.
Choose wrong, and he’ll lose everything.