takt op. 薔薇の弾丸で撃て！

Let us begin... Fight for life and regain our joy! This is the prequel story to the game takt op. Symphony, featuring the musicart "Joy"! The musicart Joy, who has the power of music in her body, and Franz, an ordinary human soldier, did not get along at first. But they must work together to fight "D2," the entity that brings about disaster... (Source: ComicWalker, translated)