Darrow is a Red, a member of the lowest caste in the color-coded society of the future. Like his fellow Reds, he works all day, believing that he and his people are making the surface of Mars livable for future generations. Yet he toils willingly, trusting that his blood and sweat will one day result in a better world for his children. But Darrow and his kind have been betrayed. Soon he discovers that humanity reached the surface generations ago. Vast cities and lush wilds spread across the planet. Darrow—and Reds like him—are nothing more than slaves to a decadent ruling class.

On a mountainside at the edge of the Kaigenese Empire live the most powerful warriors in the world, superhumans capable of raising the sea and wielding blades of ice. For hundreds of years, the fighters of the Kusanagi Peninsula have held the Empire's enemies at bay, earning their frozen spit of land the name "The Sword of Kaigen". Born into Kusanagi's legendary Matsuda family, f14-year-old Mamoru has always known his purpose: To master his family's fighting techniques and defend his homeland.

A man. His ex-girlfriend's cat. A sadistic game show unlike anything in the universe: a dungeon crawl where survival depends on killing your prey in the most entertaining way possible. In a flash, every human-erected construction on Earth - from Buckingham Palace to the tiniest of sheds - collapses in a heap, sinking into the ground. The buildings and all the people inside have all been atomized and transformed into the dungeon: an 18-level labyrinth filled with traps, monsters, and loot.

The Catenan Republic—the Hierarchy—may rule the world now, but they do not know everything. I tell them my name is Vis Telimus. I tell them I was orphaned after a tragic accident three years ago, and that good fortune alone has led to my acceptance into their most prestigious school. I tell them that once I graduate, I will gladly join the rest of civilized society in allowing my strength, my drive, and my focus—what they call Will—to be leeched away and added to the power of those above me, as millions already do. As all must eventually do.

It has been 20 years since the end of the war. The dictatorial Augurs, once thought of almost as gods, were overthrown and wiped out during the conflict, their much-feared powers mysteriously failing them. Those who had ruled under them, men and women with a lesser ability known as the Gift, avoided the Augurs' fate only by submitting themselves to the rebellion's Four Tenets.