In the year 1935 E.C., the continent of Europa is dominated by two superpowers: The autocratic East Europan Imperial Alliance in the east and a commonwealth of loosely allied democracies known as the Atlantic Federation in the west. The economies of both powers depend on a precious multipurpose mineral called Ragnite. Its growing scarcity results in the Empire declaring war on the Federation, sparking the Second Europan War. The Empire uses its military superiority to quickly put the Federation on the defensive. Emboldened by their progress and momentum, the Empire decides to invade the neutral Principality of Gallia in order to seize its rich Ragnite deposits.

When Imperial forces launch an attack on the Gallian border town of Bruhl, Welkin Gunther, son of late Gallian national hero General Belgen Gunther, is forced to fight for his life alongside the town watch captain, Alicia Melchiott. Together with Welkin's adopted sister Isara and using Belgen's prototype tank from the first war, the Edelweiss, they escape to Gallia's capital, Randgriz, and subsequently join the country's militia forces. Welkin is given the rank of lieutenant and assumes command of the newly-formed Squad 7, with Alicia acting as his non-commissioned officer. Initially, members of the squad question Welkin's qualifications due to a lack of combat experience; however, he quickly earns their trust and loyalty with his tactical genius. Welkin and Alicia soon become romantically engaged.