Raizel, protector of the nobles, along with his loyal butler Frankenstein and former Union experiment M-21, continue to spend their days at Ye Ran High School while keeping their true identities secret. They were living their lives as normal until one day, when a violent gang barges onto the school grounds. M-21 is forced to make a choice in order to protect the students. Meanwhile, DA-5, a mysterious special forces team, is dispatched to Japan on an investigative mission. What will become of the trio's peaceful new life?