Yuuki Yuuna is a Hero: Washio Sumi's Chapter 1 - Friends

In the year 298 of the Divine Era, elementary school girls Washio Sumi, Nogi Sonoko, and Minowa Gin are charged with a pivotal mission: to become heroes and confront Vertex, a mysterious enemy that attacks Shinju-sama, the god tree protecting Shikoku—the only area in the world that remains habitable. What they don't know is that this battle will cost them more than they could have ever imagined.