Young princess Fine, the daughter of the Archduke of a small alpine country, travels to the neutral land of Westria to seek help against the Germanian empire that is invading her kingdom. But her plans go awry when she's captured by the Germanians, and transported by air back to their capital of Neu-Berlin. Then a strange light appears at the back of the plane, and a witch begins to awaken...

Fine and Izetta escape the burning wreckage of the plane on the back of a rifle. But squad of Germanian pilots participating in the invasion of Eylstadt hear the transport's distress call and move to intercept them. Izetta is forced to use her magic to fight them off, breaking the rule her grandmother gave her. When the enemy planes are shot down and driven away, Izetta takes Fine to join the retreating Eylstadt army, where she reminisces about how they met.

The Germanians forces are rolling up an important strategic area, and it's only a matter of time before the dukedom's defenses fall. Waves of bombers are striking from the skies, and an entire company of tanks is tearing apart the helpless infantry. But when all seems lost, a red-haired witch appears from the skies...

With Izetta's victory over the Germanian army fresh in people's minds, the army of the Dukedom decides to make her into a national icon and announce her to the world. She's given the finest white dress they have to offer and a huge ceremony is arranged with journalists from all over the globe. But before she can be used in combat, they need to unravel the secret of her strength, which means she must travel to a hidden location with a girl who doesn't like her very much at all.

Izetta is powerful enough to fight whole armies, but her strength is limited. She can only use her abilities near certain ley lines, and outside them, she's no different than a normal girl. When the Germanian army attacks in a spot far from these ley lines, the duchy is forced into a corner: how can they repel these foes without giving up the secret of Izetta's strength?

Izetta's victory has won a brief peace for the dukedom, and the princess intends to enjoy it. Together, they practice dancing, and go to a pie shop. But there's trouble brewing in the background, as young private Jonas has discovered her secret. How far is Seig willing to go to keep the country safe, especially when innocents are involved?