The movie opens with a battle scene where Major Tanya Degurechaff and her battalion are fighting against the Republic's soldiers to the south. Tanya, known as the "Devil of the Rhine," is a ruthless and talented air mage who spares no mercy for her enemies. She leads her battalion to victory and returns to the capital city where they are greeted as heroes.
However, their victory celebration is cut short when they receive orders from Staff HQ to prepare for a new mission. The Federation, a powerful neighboring country, is massing troops on the border, and the Empire fears an imminent attack. Tanya and her battalion are deployed to the front lines to defend against the enemy.
As they journey to the border, Tanya and her soldiers encounter numerous challenges, both on the battlefield and off. They face treacherous weather conditions, sabotage from enemy spies, and internal conflicts within their own ranks. Tanya is also forced to confront her own beliefs and values when faced with the realities of war and the moral dilemmas it presents.
Despite the odds against them, Tanya and her battalion fight fiercely to defend their country. The battle scenes are intense and realistic, demonstrating the power and devastating effects of magical warfare. Tanya's tactical genius and fighting skills are put to the test as she leads her soldiers into battle after battle.
In the end, Tanya and her battalion emerge victorious, but not without paying a heavy price. The toll of war on both the soldiers and civilians is explored in-depth, as well as the political and social ramifications of conflict. The movie ends on a bittersweet note, leaving the audience with a sobering reminder of the true cost of war.