In a dystopian future, humanity is divided into two classes: the immortal Eternals and the mortal Brutals. The Eternals live in protected, advanced communities called Vortices, while the Brutals inhabit a harsh wasteland called the Outback, isolated by a force field. The Eternals, who view the Brutals as primitive, use them for labor and sustenance. They have manipulated the Brutals by creating a false religion centered around a god named “Zardoz,” invented by the Eternal Arthur Frayn.

The Brutals worship Zardoz, giving up their crops in exchange for his supposed teachings. Within the Brutals, there are two classes: the laborers who farm and the genetically enhanced "Exterminators" who enforce order. The story begins in the year 2293, highlighting the societal structure and tensions between these two groups.