Elena, a 30-year-old vampire hunter, is sent undercover into Blackwood Manor, posing as a housekeeper to kill Lucien, a vampire who has lived in seclusion for 300 years. She arrives armed with silver weapons and holy water, only to find that her target sleeps by day, walks by night, and never touches a human. Instead, he's been funding medicine for the nearby town, hunting down werewolves, and protecting local residents. Lucien sees through her cover when they first meet. However, he lets her stay and tests her while keeping her safe.
Later, Elena discovers the truth of her father's death. Her father wasn't killed by a vampire. He was silenced in a power struggle, and the Church has been lying to vampire hunters for years, sending them to slaughter the innocent. Werewolf attacks, the Church's assassins, secrets in the cellar, and the blood thirst Lucien fights to control, all of it draws Elena and Lucien closer. The hunter and prey become the only light in each other's life.
In the end, Elena turns against the Church and stands with Lucien against the Church's assassins and the evil vampires. In the final battle, Lucien takes a silver arrow for her and nearly dies. Elena saves him with her hunter's blood, thus they are bound to each other for good. They burn the Church's stronghold to the ground, destroy their enemies, and leave everything behind to start over in the Far North. Under the northern lights, it's just the two of them, together at last.
