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!

Rido is gone, but the battle rages on at Cross Academy. The Night Class is still under attack, and Headmaster Cross has joined the war to protect his students. Zero, however, has vowed to get rid of all the Purebloods--including Yuki!