Kazuki Hyoudou is the younger twin of Issei Hyoudou, since birth they've always been opposites despite being twins. Issei has always been the straightforward older brother who charges into every situation with his strong emotions and undeterred feelings. While, Kazuki has always been the more careful younger brother who goes into a situation using his quick intuition and adaptability. Both attends Kuoh Academy as second-year students, and as lived peaceful lives with their families. However, their adventures start when a new girl by the name of Yuuma Amano transfers into the same class as them and she soon asks Kazuki on a date.