The comic adaptation of the TV anime "Washio Sumi no Shou" has proudly concluded! Set two years before "Yuki Yuna is a Hero," in the year 298 of the Divine Era, sixth grader Washio Sumi, along with Nogi Sonoko and Minowa Gin, continues the fight to protect the world from the mysterious monsters known as Vertex. To defeat the ever-evolving Vertex, Sumi and her friends are granted the "Hero System." However, unbeknownst to them, activating this system requires the hero to make a harsh sacrifice, and they head into the final battle without knowing this truth――!!