In the midst of Europe's invasion by the Holy Britannian Empire in 2017, the military forms a special unit, Wyvern (W-0), comprised of former Japanese citizens known as 'Elevens' to counter the enemy's relentless advance. Recruited from impoverished areas, these young individuals pilot Knightmare frames, humanoid war machines, in perilous missions where danger lurks at every turn, aiming to carve a legacy for themselves. Tasked with rescuing a besieged European regiment in a vital city, W-0, including the skilled Lieutenant Akito Hyuuga, nicknamed 'Hannibal's Ghost' for his battlefield prowess, steps up to the challenge. However, what begins as a rescue operation takes a dark turn as the commanding officer, in a desperate bid to inflict maximum damage on the Britannian forces, triggers the Knightmare's self-destruct sequence, turning the mission into a suicide mission. In the aftermath, Akito emerges as the sole survivor, grappling with the aftermath of the devastating event.