Local heroines—superhero characters that represent communities and conduct stage acts to increase their town's acclaim—were very popular a few years ago. Mikan Kise's younger sister Yuzu is very excited because the most famous of these local heroines, Kamidaio, is due to appear in the small town of Hinano. Mikan is disappointed to learn that the show has been canceled when she takes Yuzu to it. She assures her worried sister that she will be able to witness the show. Mikan begs her classmate, local heroine fanatic An Akagi, for assistance, desperate not to let her down.