The story of the Kamen Rider Fourze Movie·Fourze OOO Movie vs. Megamax is summarized as follows: In Masked Rider Fourze's worldview, as new enemies and missions constantly appeared, Fourze and his friends had to unite to fight against the enemies that threatened the world. In this movie, Megamax appeared as a new enemy, and Fourze and his friends had to unite to fight against this powerful enemy. The story follows the battle between Fourze and his friends and Megamax, and how they defeat the enemy through cooperation and unity. In this battle, Fourze and his friends must use all their skills and abilities, including the power of the Masked Knight, special abilities, weapons, and magic to defeat Megamax. In the end, they successfully defeated Megamax and protected world peace.