Divine Era, year 298, two years before "Yuuki Yuuna's Chapter", Washio Sumi who was chosen by Shinju-sama, is a hero who protects the world alongside her classmates, Nogi Sonoko and Minowa Gin. It seems like Sonoko and Gin are trouble-makers because they could be idiotic or too energetic. Sumi is excited that she should lead the other two, but...
