The Moonfall series Tome 1
When the Moon Hatched

As an assassin for the rebellion group Fiur du Ath, Reeve's job is to complete orders and never get caught. When a rival bounty hunter turns her world upside down, blood spills, hearts break, and Raeve finds herself imprisoned by the Guild of Nobles-a group of powerful fae who turn her into a political statement. Crushed by the loss of his great love, Kaan Vaegor took the head of a king and donned his melted crown.
Now on a tireless quest to quell the never-ebbing ache in his chest, a clue lures him into the capital's high-security prison where he stumbles upon the imprisoned Raeve... Echoes of the past race between them. There's more to their story than meets the eye, but some truths are too poisonous to swallow.