Mobile Suit Gundam: Battle Operation Code Fairy tells the story of the “Noisy Fairy”—a secret unit led by Alma and under the direct control of Kycilia of the Principality of Zeon. During the “One Year War,” the unit struggles to break through the North America continent.

In order to break through the deteriorating war situation in the North American continent, the "Noisy Fairy", a secret unit under the direct control of Kycilia of the Principality of Zeon, led by Alma, is pushing forward in the "One Year War" against the Earth Federation Forces, which possess the White Devil. The soldiers take on the brutality of war and grasp the unshakable bonds between their comrades... Universal Century 0079: Flowers bloom even in the flames of war.