Four years later, Yuichiro Hyakuya is a soldier in the Japanese Imperial Demon Army, but he gets suspended for insubordination. As punishment, he attends a school with the order to "make friends.

Mikaela, who was thought to be dead, was actually turned into a vampire by Krul and is working with them. Meanwhile, Yuichiro starts his first day at the Extermination Unit's training school, and already he gets into a fight with one of his classmates...