鷲尾須美は勇者である

In year 298 of the era of the gods the Taisha calls up three sixth-graders, and Sumi Washio takes the lead with Sonoko Nogi and Gin Minowa beside her. The Shinju's barrier is the only reason Shikoku is still habitable, and the Vertex come out of the sea to bring it down. Sumi fights with a bow, Sonoko with rounds that change shape, Gin with twin axes. This light novel is the source the Washio Sumi Chapter films and manga follow.