People with strong attachments to life are guided to a world called Kuu, a place between life and death, when they are on the brink of death.
In this world, there is a battle called The Fate Ring, where participants control mechas to fight. The winner of the ring battle is given a chance to come back to life.
A carefree girl named Kaname Kaname falls into Kouku, where she unexpectedly meets the most terrifying helmet-wearing warrior, Saburo. Together, they form an unlikely partnership, searching for a way to survive the Fate Ring and claim the opportunity for life.
"Without the past, there is no meaning to the life I've lived. I will fight to reclaim my future."