The Cross Academy hosts two groups of students: the Day Class and the Night Class. In the evening, when the Day Class students return to their dorms, 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 dark secret of the Academy: the Night Class is filled with vampires! A war among vampires has begun at Cross Academy, and even the Day Class students are being attacked. Kaname ultimately reveals his hidden plan to Zero, and Zero must choose a side in the war. But to defeat the enemy, Zero will have to partake in a horrific act...