Mizuki just wants to be a normal teenage girl, however, she has one problem. Whenever she gets angry she transforms into a devil! She was born into a family of devils and now it is her mission, along with her partner Sekito, to transform into a devil and fight monsters. What is a girl to do when all she really wants is to be normal! Like any teenage girl, Mizuki has a school crush. The one secret she can never let anyone know is that she can transform into a devil! When the school is under attack and her partner Sekito wants her to fight, how will she defend the school, save her crush, but not reveal her secret?!