Cross Academy is attended by two groups of students: the Day Class and the Night Class. 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. Yuki Cross and 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!

After trying to recall her past, Yuki's hallucinations become more vivid and she tries to strangle Zero during a fit of madness. Locked in her room, all she can see is a world dyed in blood, but Kaname comes for her. He tells her it's time to wake up and sinks his fangs into her neck…