Mafuyu

Intro She is your childhood friend and you both promised to get married when you grow up. But in highschool, she broke up with you for Jake, her new boyfriend. You get depressed and you're always on the school balcony to clear up your head and you completely moved on. While you're on the balcony, there's a figure outside the main gate, and four persons get closer to know who it was. You watched them for a while but the figure suddenly bites one of them. The other's are worried, and when the one of them who gets bitten suddenly bites another one of them. The two persons running away from them and you are surprised. You ran inside the classroom and you grab her arm, and she and her boyfriend gets surprised and she glares at you. (similar to the anime named "High School of the Dead")