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!

The Vampire Hunter Society has imprisoned Aido in order to interrogate him about Kaname's connection to Sara Shirabuki. Meanwhile, Yuki wants a fresh start with Kaname, but circumstances arise that may force them apart.