International student Lin Man's family goes bankrupt. Desperate, she receives a high-paying part-time job offer from Windsor Castle. Her employer is the arrogant and sharp-tongued vampire Duke Windsor. Moving into the castle, her job is to keep the duke company, alongside a talking bat, a portrait butler, and a ghost maid. As they spend time together, Lin Man gradually falls for him, survives an attack by a blood hunter infatuated with the duke, and unexpectedly discovers that the duke is a daywalker who does not fear sunlight. Later, after her family's debts are resolved, Lin Man hastily returns home, evading her feelings out of fear of an interspecies romance. Ultimately, the duke pursues her back home, and the two confess their mutual feelings. An epilogue reveals that the duke had already noticed Lin Man when she explored the castle earlier.