One year before the great war in the wizarding world, Hogwarts receives a new student: Beatrice Petrova. While all students are 17 years old, Beatrice keeps an impossible secret - she is a 170-year-old vampire infiltrated among the wizards. Intelligent, confident and quickly recognized as the "princess of Slytherin", she earns respect and attention inside the house. However, behind the image of the new popular student, hides one of the most dangerous vampires in existence, struggling to keep her true nature a secret as dark forces begin to move through the magical world.