Yuuki Yuuna wa Yuusha de Aru

Japanese Title: 結城友奈は勇者である

English Title: Yuuki Yuuna is a Hero

Plot
The story takes place in the era of the gods, year 300.

Yūna, Mimori, Fū, and Itsuki lives an ordinary life as second year middle school students and are all members of the Sanshu Middle School Hero Club (讃州中学勇者部 Sanshū Chūgaku Yūsha-bu?), dedicating themselves to helping those that requested and where club activities involve dealing with a mysterious being called "Vertex." One day, they are suddenly caught in a ray of light and transported to a strange forest, where evil monsters known as Vertex are seeking to destroy the Divine Tree (神樹 Shinju?), which would in turn destroy the world. Using a special app to transform into magical girls, Yūna and the others must now become true heroes in order to protect their world.