It was a forbidden love.  It was a one-sided love. Tao was a werewolf, and part of the pack called Exo. Kim Miyeon was a simple human with a simple life.  When the two meet, something terrible happens.

He becomes desperately, impossibly in love with her, and won't allow anything to hurt her, especially himself. 

She would rather have him eat her, like he should have; this strange attraction he had to her scared her a great deal, and she was even more afraid of herself accepting and returning it.   

However, even if she did fall in love with him, it wouldn't matter.  Either she would die, Tao would die, or they both would.