Monsters suddenly appeared in this world. Those monster is called “Wanderer”. Just when it seems humanity is in danger of destruction, a mysterious entity called magical girls appears. On the other hand, a man who has longed to be a hero since childhood still cannot give up on his dream even after becoming an adult. Even if the reason for that is not because he wants to save or help someone, but just because he wants to be a hero. One day, he receives an invitation from a mysterious creature to become a hero. It’s clearly an abrupt and suspicious invitation. But to that suspicious invitation that might never come once more, the boy decides to accept it. “Transform!” The man who fulfilled his dream of becoming a hero, as the magical girl “Blackrose” and saves the world!