Woo-ju, a model student and class president who has devoted everything to getting into medical school, finds his life turned upside down when Pi Na-young, a vampire transfer student from Romania, arrives at his school. After accidentally becoming the keeper of her secret, Woo-ju finds himself looking after both her studies and school life. As the two constantly bicker and clash, unfamiliar feelings begin to blossom between them, leaving Na-young increasingly confused as she struggles to tell whether her racing heart for Woo-ju is the feeling of falling in love or simply her vampire instincts.