When Kate's dearest childhood friend returns to warn her of danger, she's not happy to see him. After all, Cor isn't really a monster-slaying master swordsman from another world. He's a hallucination. Kate spent years in a mental ward for believing otherwise.

Cor did his best to honor Kate's wishes when she sent him away five years ago, staying in the shadows to keep her safe. Her own family abandoned her because they couldn't see him the way she could, leaving her easy prey for Hunters from his world. Cor couldn't leave her to die, not when he had the power to protect her.

If Kate returns to his world and learns how to defend herself, he'll walk out of her life forever, just like she wants. Cor's world is wilder than Kate

remembers and Cor is keeping secrets, but the more time they spend together, the more she sees in him the boy she used to love. If Cor is real, so are the monsters, and it's getting harder to imagine saying goodbye.