Sumi Washio is in her last year of elementary school when the Taisha names her a Hero, together with Sonoko Nogi and Gin Minowa. In year 298 of the era of the gods the Vertex keep coming for the Shinju, the divine tree whose barrier leaves Shikoku the only habitable land on earth. The three answer with a bow, shape-shifting rounds and a pair of outsized axes. Class and chores fill the hours between deployments. This manga sets its story two years before the Hero Club's.