The band has lost a lottery to play in the main stage of the cultural fair, but they decide to take part in a survival game. If they win the game, they can take two seats in the music room even if they enter late, and they get to decide whether or not they want to enter late. The situation is reversed now that the enemy has moved into the second floor of the building. The enemy is behind them, and the only way they can get back is to get a signal from the sawachika, which is hidden in the corner of the room. They can also get the flag, which they can use to confuse the enemy and lull them into false security. They lose two more battles, but now they have a chance to catch the enemy in a trap.