Embrace The Night - Chance, Karen

As long as Cassie and Mircea are magically bound to each other, her life will never be her own. The spell that binds them can only be broken with an incantation found in the Codex Merlini. The Codex's location has been lost so Cassie will have to seek it out in the past. But she soon realizes the Codex has been lost for a reason.