In her everyday life, Yuuna Yuuki exemplifies heroism. As a member of her school's Hero Club, her primary goal is to assist and bring happiness to those around her. However, her courage is soon put to the test as a group of destructive beings, known as Vertexes, threaten her beloved planet. Through a mysterious phone application, the Hero Club is called to action. With the support of her closest ally, Mimori Tougou, and siblings Fuu and Itsuki Inubouzaki, Yuuna becomes a magical girl to face the Vertexes. Alongside their studies and performances for children, Yuuna and the Hero Club confront the truth about their own powers and fight for the survival of their world. They discover the true essence of heroism with ease.