It takes place in a small room, where our player is waken up by a strange man in the middle of the night. This man leaves clues here and there in the room, to lead the player to his, so called,
@Xdqwerty, Osu! Tatakae! Ouendan! is the Japanese version of the game, different settings/characters/songs but otherwise identical mechanics. I played that before I knew about Elite Beat Agents lol. Both fantastic games https://en.wikipedia.org/wiki/Osu!_Tatakae!_Ouendan