Actually, I am... Episode 13

One day after school, Asahi Kuromine stumbles upon the truth that Youko Shiragami, the girl he has a crush on, is actually a vampire. According to her father's rules, Youko must now quit school in order to keep her family safe. However, Asahi does not want her to go and promises that he will keep her true nature secret. Unfortunately, this turns out to be easier said than done, as Asahi is a man w