In the Unified Year 1926, Major Tanya von Degurechaff and her 203rd Air Mage Battalion have won the battle against the remnants of the Republic forces on the southern continent. They return in triumph, expecting that they will be given a well-deserved vacation. However, what awaits them is a special order from Command. They are informed there are signs of a large-scale mobilization near the Empire-Federation border. Faced with an awakening giant, the Empire desperately needs to consolidate their position. Meanwhile, a multinational volunteer army led by the Allied Kingdom enters Federation territory. As they say, the enemy of an enemy is your friend. Motivated by national interests, this group will suffer from misfortune. Among them is a girl, Warrant Officer Mary Sue. She takes up her rifle, eager to bring the Empire, who killed her father, to justice.
