An alien corps appears to misfortune the peaceful planet! The Blue City is deeply saddened by guitar melodies played by alien "U2". In order to fight the alien corps that is stronger than the villains they used to deal with, Miniforce accepts the mysterious energy, "X-POWER" with the power of beast!

The stronger U2 is back in the Blue City. The performance of U2 spreads all over the place, and it becomes bigger and bigger, and terrorizes the city! Miniforce summons the most powerful robots, the "Force X bot", to defeat the giant U2! Will they be able to defeat U2 and regain peace in the city?