Twenty years after the “Sky Fracture” shattered the balance of the world, four childhood friends—once just ordinary kids—now struggle to survive across the four continents born from that catastrophe.
Each of them bears a power ranked at the very bottom — Rank F.
Kudo Ren can only teleport without control, Toma devours anything without getting full, Kurogane gambles with his own fate, and Mira can merely attract animals.
But when a Class-S monster attack strikes their city, a deadly wager begins.
And amid laughter and despair, the cracks of their past begin to open… once again.