Book 2 of The Haunted Hearts Series:

Hazel is trapped in a dangerous world, in his world. Who will she become in this place? Can she ever find her way home?
She doesn't remember who she is or how she got here. What she does know is that something isn't right. Darkness creeps across the land, a castle is shrouded in perpetual fog, and people appear out of thin air. There are also monsters and magic spells.
And two identical guys who hate each other vying for her attention. Which one can she trust?