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 Night Class at Cross Academy has been abolished. Zero still attends the Day Class while carrying out his duties as a vampire hunter. Yuki now lives hidden away at the Kuran residence with Kaname, but can she embrace the life of a pureblood vampire?