Our story starts with a girl named Rachel Hazukashi. She attends a famous boarding school named Cross Academy. Cross Academy has two classes: the Day Class, who live in the Sun Dormitories, and the Night Class, who live in the Moon Dormitories. At twilight, when the students of the Day Class return to their dorm, they cross paths with the Night Class on their way to school. Rachel and her best friend Maxine Jonokishi, along with their friend Zero Kiryu are the Guardians of the school, protecting the Day Class from the Academy's dark secret: the Night Class is full of vampires. With the assistance of Night Class President Kaname Kuran, Headmaster and former legendary Vampire Hunter Kaien Cross works to prove vampires and humans can coexists peacefully.