An adventure game based on the TV anime `Sound of the Sky`. Members of the 1121st Platoon, a defense unit composed entirely of girls, are depicted struggling to perform at a music festival. Original characters that are not in the original also appear, and the story progresses with a little fan service happening. This work adopts a multi-view system, and the player can select the character who will be the `hero of the day` for each day and enjoy the scenario from each viewpoint. In addition, a parameter called `playing ability` is set for each character, and the playing ability goes up and down in daily events, and everyone's level can be confirmed `by ear` in daily practice.