The story takes place in the era of the gods, year 300. Yuuna Yuuki lives an ordinary life as a second year middle school student, but she's also a member of the Hero Club, where club activities involve dealing with a mysterious being called Vertex. (Source: ANN)

In her everyday life, Yuuna Yuuki is a hero. As proof, she is in her middle school's Hero Club, where she does her best to help others and bring a smile to everyone's face. But Yuuna, always up to any task, is about to become an even bigger hero. Mysterious destructive forces called Vertexes begin threatening the world she loves, and the Hero Club is called upon by a strange phone app to save it. Along with her best friend Mimori Tougou, as well as sisters Fuu and Itsuki Inubouzaki, they must transform into magical girls in order to battle the Vertexes. In between studying and putting on shows for kids, Yuuna and the Hero Club must fight for the very existence of their world and face the harsh truths behind their own powers, all the while discovering what it truly means to be a hero.

At the cost of the gods' protection, a new era has dawned, giving the remnants of mankind a chance to rebuild. Having fulfilled their duties to Taisha, the members of Sanshu Middle School's Hero Club finally begin to enjoy their youth, living as regular students. However, such a conclusion did not come about without sacrifice. In the year 298 of the Divine Era, Mebuki Kusunoki is among the potential candidates to become the next hero. Despite her painstaking efforts to surpass her competition, she loses the position to Karin Miyoshi, leaving Mebuki furious at Taisha's decision. Two years later, Mebuki is appointed commander of the Sentinels—a group tasked to explore uncharted territory beyond the barrier. The team's seemingly simple mission is quickly disrupted by unforeseen threats, endangering the innocent lives of the fleet. To prove her worth as a hero, Mebuki vows to bring everyone back alive, no matter what it takes.

During the late 19th century, Great Britain has become the greatest empire the world has ever known. Hidden within its success, the nation's rigid economic hierarchy dictates the value of one's life solely on status and wealth. To no surprise, the system favors the aristocracy at the top and renders it impossible for the working class to ascend the ranks. William James Moriarty, the second son of the Moriarty household, lives as a regular noble while also being a consultant for the common folk to give them a hand and solve their problems. However, deep inside him lies a desire to destroy the current structure that dominates British society and those who benefit from it. Alongside his brothers Albert and Louis, William will do anything it takes to change the filthy world he lives in—even if blood must be spilled.