In a distant future, Earth has become a wasteland and humanity as we know it has died out. All that remains are sentient robots. They were supposed to be able to live forever—until the one called Luna died and the Ruin started. Their bodies will rust, and there is nothing that can be done to fix it. Now the robots are left only to contemplate their deaths, kept going only by the rumor that if they eat the one called Casshern, they will gain immortality. Casshern knows nothing about his past, why he exists, or what he is, but he must find out, or he will face the constant torment of being hunted by robots who don’t want to die. Casshern leaves death wherever he goes, but he must face it if he is to find out the truth of this world. [Written by MAL Rewrite]

In the backwater town of Bellforest lives a 14-year-old boy named Renton Thurston. He desires to leave his home behind and join the mercenary group known as Gekkostate, hoping to find some adventure to brighten up his mundane life. However, stuck between his grandfather’s insistence to become a mechanic like him and the pressure of his deceased father’s legacy, the only excitement Renton finds is in his pastime of riding the Trapar wave particles that are dispersed throughout the air, an activity akin to surfing. Everything changes when an unknown object crashes through Renton’s garage, discovered to be a Light Finding Operation—a robot capable of riding the Trapar waves—specifically known as the Nirvash typeZERO. Its pilot is a young girl named Eureka, a member of the Gekkostate, who requests a tune-up for the Nirvash. Their meeting sparks the beginning of Renton’s involvement with the Gekkostate as he takes off alongside Eureka as the co-pilot of the Nirvash. [Written by MAL Rewrite]