In the early 20th century, a small republic found itself stuck between a kingdom and an empire - both of whom wanted to manipulate the republic to suit their own needs. In order to protect itself from both sides of the conflict, the republic created a small group of soldiers whose job it is to suppress revolution and dissent in any way possible. This is the story of the Opera House. From the author of [*Youjo Senki*](https://mangadex.org/title/18803)."