Demon is set in Victorian London and has a great gothic tone while pulling off the love story feel. A young man named Lorcan visits the London Hospital for the treatment of a blood disorder. Lorcan meets his love interest Amy, a young nurse and sparks fly. Lorcan soon unravels a mystery that he is cursed from birth. The curse entails that if he loves or becomes loved, he will turn into a living demon. Lorcan soon starts transforming with only Amy to save him.